refactor: Migrate mongodbatlas_encryption_at_rest to Terraform Plugin Framework

[maastha]

Description

Please include a summary of the fix/feature/change, including any relevant motivation and context.

Link to any related issue(s):

Type of change:

• Bug fix (non-breaking change which fixes an issue). Please, add the "bug" label to the PR.
• New feature (non-breaking change which adds functionality). Please, add the "enhancement" label to the PR.
• Breaking change (fix or feature that would cause existing functionality to not work as expected). Please, add the "breaking change" label to the PR.
• This change requires a documentation update
• Documentation fix/enhancement

Required Checklist:

• I have signed the MongoDB CLA
• I have read the contribution guidelines
• I have added tests that prove my fix is effective or that my feature works per HashiCorp requirements
• I have added any necessary documentation (if appropriate)
• I have run make fmt and formatted my code

Further comments

Migration and acceptance tests run locally:

Import:

Resource in state after import:

  {
      "mode": "managed",
      "type": "mongodbatlas_encryption_at_rest",
      "name": "example",
      "provider": "provider[\"registry.terraform.io/mongodb/mongodbatlas\"]",
      "instances": [
        {
          "schema_version": 0,
          "attributes": {
            "aws_kms_config": [
              {
                "access_key_id": null,
                "customer_master_key_id": "arn:aws:kms:us-east-1:....................xxxxxxxxxxxxxxxxxxxxxxxxxx",
                "enabled": true,
                "region": "US_EAST_1",
                "role_id": "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
                "secret_access_key": null
              }
            ],
            "azure_key_vault_config": [
              {
                "azure_environment": "",
                "client_id": "",
                "enabled": false,
                "key_identifier": "",
                "key_vault_name": "",
                "resource_group_name": "",
                "secret": null,
                "subscription_id": "",
                "tenant_id": ""
              }
            ],
            "google_cloud_kms_config": [
              {
                "enabled": false,
                "key_version_resource_id": "",
                "service_account_key": null
              }
            ],
            "id": "63bec58b014da65b8f73c06c",
            "project_id": "63bec58b014da65b8f73c06c"
          },
          "sensitive_attributes": []
        }
      ]
    },

[andreaangiolillo]

LGTM

[andreaangiolillo]

Was this logic already here? Can we use retry.StateChangeConf instead? you can file a ticket to improve the logic to use retry.StateChangeConf

[maastha]

yes, this has been migrated as is. Created https://jira.mongodb.org/browse/INTMDB-1039