Add control status icon to Terminal header

[jpellizzari]

Implements #1982

This change will indicate the control status of the terminal. For example, if you are using the exec control a terminal icon will appear in the upper left (same for the 'attach' command):

The icon is tightly coupled to the human name of the controls: "Attach" and "Exec shell". This will break if we ever change those values. If there is a different value to lookup (like an ID) that might be better.

@foot could you review please?

[foot]

Slick! Like the design.

raw: true|false aligning w/ the icons is a bit co-incidental, though its a bummer to add more state it would be nice to record the icon of the control that created that pipe and use that explicitly. If you save it into the controlPipe object next to the raw status it should be de/serialized into the url state for reloads and what not.

[jpellizzari]

@foot Updated to use the 'icon' field of the control. Thanks, that's much better.

[foot]

Nice.

There's a bit of awkward implicitness in how we do the url state stuff.

As the entire control is being saved into the controlPipe you get a bit of unused info ( controlPipe.control.{id,probeId,human,nodeId}) up in there:

{
    "controlPipe": {
        "control": {
            "human": "Exec shell",
            "icon": "fa-terminal",
            "id": "docker_exec_container",
            "nodeId": "6229d32d614b8f7bc0ee51791ddf197de5a9d3c950a31e441082ab9528855f2c;<container>",
            "probeId": "392656d14781da1e",
            "rank": 2
        },
        "id": "pipe-5735362070544949278",
        "nodeId": "6229d32d614b8f7bc0ee51791ddf197de5a9d3c950a31e441082ab9528855f2c;<container>",
        "raw": true,
        "resizeTtyControl": {
            "id": "docker_resize_exec_tty",
            "nodeId": "6229d32d614b8f7bc0ee51791ddf197de5a9d3c950a31e441082ab9528855f2c;<container>",
            "probeId": "392656d14781da1e"
        }
    },
    "gridSortedBy": "label",
    "gridSortedDesc": false,
    "nodeDetails": [
        {
            "id": "6229d32d614b8f7bc0ee51791ddf197de5a9d3c950a31e441082ab9528855f2c;<container>",
            "label": "weavescope-app",
            "topologyId": "containers"
        }
    ],
    "pinnedMetricType": null,
    "pinnedSearches": [],
    "searchQuery": "",
    "selectedNodeId": "6229d32d614b8f7bc0ee51791ddf197de5a9d3c950a31e441082ab9528855f2c;<container>",
    "topologyId": "containers",
    "topologyOptions": {
        "containers": {
            "container-label-filters-group": "all",
            "pseudo": "hide",
            "stopped": "both",
            "system": "both"
        },
        "processes": {
            "unconnected": "hide"
        }
    },
    "topologyViewMode": "topo"
}

But actually its not the worst thing in the world, we might need that info in the future. We have another ticket #1727 for tightening up the url state.

LGTM!