feat(ws): refactor backend models and repositories

[thesuperzapper]

closes: #127
closes: #128

What does this PR do?

This PR significantly refactors the Notebooks 2.0 backend API:

1. Factors out the models and repositories into sub-folders for each of healthcheck, namespaces, workspaces, and workspacekinds.
2. Slightly changes the API response formats (see below for sample responses).
3. Fixes the case when a Workspace uses a WorkspaceKind that does not exist:
   • We now just populate any unknown fields with default values like __UNKNOWN_POD_CONFIG__ and __UNKNOWN_IMAGE_CONFIG__.
4. Updates a lot of tests.

Sample API Responses

List WorkspaceKinds

curl -i localhost:4000/api/v1/workspacekinds

{
    "data": [
        {
            "name": "jupyterlab",
            "display_name": "JupyterLab Notebook",
            "description": "A Workspace which runs JupyterLab in a Pod",
            "deprecated": false,
            "deprecation_message": "This WorkspaceKind will be removed on 20XX-XX-XX, please use another WorkspaceKind.",
            "hidden": false,
            "icon": {
                "url": "/workspaces/backend/api/v1/workspacekinds/jupyterlab/assets/icon"
            },
            "logo": {
                "url": "/workspaces/backend/api/v1/workspacekinds/jupyterlab/assets/logo"
            },
            "pod_template": {
                "pod_metadata": {
                    "labels": {
                        "my-workspace-kind-label": "my-value"
                    },
                    "annotations": {
                        "my-workspace-kind-annotation": "my-value"
                    }
                },
                "volume_mounts": {
                    "home": "/home/jovyan"
                },
                "options": {
                    "image_config": {
                        "default": "jupyterlab_scipy_190",
                        "values": [
                            {
                                "id": "jupyterlab_scipy_180",
                                "displayName": "jupyter-scipy:v1.8.0",
                                "description": "JupyterLab, with SciPy Packages",
                                "labels": [
                                    {
                                        "key": "python_version",
                                        "value": "3.11"
                                    }
                                ],
                                "hidden": true,
                                "redirect": {
                                    "to": "jupyterlab_scipy_190",
                                    "message": {
                                        "text": "This update will change...",
                                        "level": "Info"
                                    }
                                }
                            },
                            {
                                "id": "jupyterlab_scipy_190",
                                "displayName": "jupyter-scipy:v1.9.0",
                                "description": "JupyterLab, with SciPy Packages",
                                "labels": [
                                    {
                                        "key": "python_version",
                                        "value": "3.11"
                                    }
                                ],
                                "hidden": false
                            }
                        ]
                    },
                    "pod_config": {
                        "default": "tiny_cpu",
                        "values": [
                            {
                                "id": "tiny_cpu",
                                "displayName": "Tiny CPU",
                                "description": "Pod with 0.1 CPU, 128 Mb RAM",
                                "labels": [
                                    {
                                        "key": "cpu",
                                        "value": "100m"
                                    },
                                    {
                                        "key": "memory",
                                        "value": "128Mi"
                                    }
                                ],
                                "hidden": false
                            },
                            {
                                "id": "small_cpu",
                                "displayName": "Small CPU",
                                "description": "Pod with 1 CPU, 2 GB RAM",
                                "labels": [
                                    {
                                        "key": "cpu",
                                        "value": "1000m"
                                    },
                                    {
                                        "key": "memory",
                                        "value": "2Gi"
                                    }
                                ],
                                "hidden": false
                            },
                            {
                                "id": "big_gpu",
                                "displayName": "Big GPU",
                                "description": "Pod with 4 CPU, 16 GB RAM, and 1 GPU",
                                "labels": [
                                    {
                                        "key": "cpu",
                                        "value": "4000m"
                                    },
                                    {
                                        "key": "memory",
                                        "value": "16Gi"
                                    },
                                    {
                                        "key": "gpu",
                                        "value": "1"
                                    }
                                ],
                                "hidden": false
                            }
                        ]
                    }
                }
            }
        }
    ]
}

List Workspaces

curl -i localhost:4000/api/v1/workspaces

{
    "data": [
        {
            "name": "jupyterlab-workspace",
            "namespace": "default",
            "workspace_kind": {
                "name": "jupyterlab",
                "missing": false,
                "icon": {
                    "url": "/workspaces/backend/api/v1/workspacekinds/jupyterlab/assets/icon"
                },
                "logo": {
                    "url": "/workspaces/backend/api/v1/workspacekinds/jupyterlab/assets/logo"
                }
            },
            "defer_updates": false,
            "paused": false,
            "paused_time": 0,
            "state": "Unknown",
            "state_message": "",
            "pod_template": {
                "pod_metadata": {
                    "labels": {},
                    "annotations": {}
                },
                "volumes": {
                    "home": {
                        "pvc_name": "workspace-home-pvc",
                        "mount_path": "/home/jovyan",
                        "read_only": false
                    },
                    "data": [
                        {
                            "pvc_name": "workspace-data-pvc",
                            "mount_path": "/data/my-data",
                            "read_only": false
                        }
                    ]
                },
                "options": {
                    "image_config": {
                        "current": {
                            "id": "jupyterlab_scipy_190",
                            "display_name": "jupyter-scipy:v1.9.0",
                            "description": "JupyterLab, with SciPy Packages",
                            "labels": [
                                {
                                    "key": "python_version",
                                    "value": "3.11"
                                }
                            ]
                        }
                    },
                    "pod_config": {
                        "current": {
                            "id": "tiny_cpu",
                            "display_name": "Tiny CPU",
                            "description": "Pod with 0.1 CPU, 128 Mb RAM",
                            "labels": [
                                {
                                    "key": "cpu",
                                    "value": "100m"
                                },
                                {
                                    "key": "memory",
                                    "value": "128Mi"
                                }
                            ]
                        }
                    }
                }
            },
            "activity": {
                "last_activity": 0,
                "last_update": 0
            }
        }
    ]
}

List Workspaces (with missing WorkspaceKind)

curl -i localhost:4000/api/v1/workspaces

{
    "data": [
        {
            "name": "jupyterlab-workspace-bad",
            "namespace": "default",
            "workspace_kind": {
                "name": "jupyterlab-bad",
                "missing": true,
                "icon": {
                    "url": "/workspaces/backend/api/v1/workspacekinds/jupyterlab-bad/assets/icon"
                },
                "logo": {
                    "url": "/workspaces/backend/api/v1/workspacekinds/jupyterlab-bad/assets/logo"
                }
            },
            "defer_updates": false,
            "paused": false,
            "paused_time": 0,
            "state": "Unknown",
            "state_message": "",
            "pod_template": {
                "pod_metadata": {
                    "labels": {},
                    "annotations": {}
                },
                "volumes": {
                    "home": {
                        "pvc_name": "workspace-home-pvc",
                        "mount_path": "__UNKNOWN_HOME_MOUNT_PATH__",
                        "read_only": false
                    },
                    "data": [
                        {
                            "pvc_name": "workspace-data-pvc",
                            "mount_path": "/data/my-data",
                            "read_only": false
                        }
                    ]
                },
                "options": {
                    "image_config": {
                        "current": {
                            "id": "jupyterlab_scipy_190",
                            "display_name": "__UNKNOWN_IMAGE_CONFIG__",
                            "description": "__UNKNOWN_IMAGE_CONFIG__",
                            "labels": null
                        }
                    },
                    "pod_config": {
                        "current": {
                            "id": "tiny_cpu",
                            "display_name": "__UNKNOWN_POD_CONFIG__",
                            "description": "__UNKNOWN_POD_CONFIG__",
                            "labels": null
                        }
                    }
                }
            },
            "activity": {
                "last_activity": 0,
                "last_update": 0
            }
        }
    ]
}

[ederign]

Thank you, @thesuperzapper, for this PR.

The code looks good to me. I'm merging this to unblock other PRs. As this is a WIP, we can always accommodate changes and evolve it later.

I've tested the scenarios listed on README, and they are working fine.

[ederign]

/lgtm

[thesuperzapper]

/approve

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