Registry phase 2 migration: New APIs required for the migration

Context

The context for this issue can be viewed in the epic &7316 (closed) and the breakdown of work can be viewed in this comment &7316 (comment 792633854).

We decided to make a unified endpoint PUT /api/:version/internal/registry/repositories/:path/migration/status that will consume the request body as defined in the import notification endpoint.

{
  "name": "gitlab-container-registry",
  "path": "gitlab-org/build/cng/gitlab-container-registry",
  "status": "imported",
  "detail": "import completed successfully"
}

The possible statuses are defined in container-registry#510 (closed)

📻 API changes

New endpoint: PUT /api/:version/internal/registry/repositories/:path/migration/status

• backend tasks:
  • Check for authentication
    • Only requests with the Container Registry secret are allowed.
  • Check for migration status coherence
  • If current status is pre_import_complete:
    • Execute container_repository.finish_pre_import
    • Execute container_repository.start_import
  • If current status is imported:
    • Execute container_repository.finish_import
    • Log all the migration_* timestamps
• Possible response codes:
  • 200 OK Everything is fine.
  • 400 BadRequest if called for a container repository that is not in the right migration state with a body similar to this one:

    { "message": "400 Bad request - Wrong migration state(<current migration state>) for status <status value sent> }

  • 401 Unauthorized if the secret is missing.