Changelog: fixed

Update the gitlab client to support the new API.
Update the ContainerRepository model with a way to iterate through tags
pages using this new API.

Added nil check

Changelog: fixed

Adds a force param to the gitlab cancel import
client endpoint.

This param is meant as a safety device so admin
users can cancel an import if needed during the Phase
2 migration.

This function will try to compute the deduplicated size of the container
repositories linked with the given project.

Changelog: added

Trigger abort request to the registry on long
running migrations.

Add a new client endpoint to abort an import.

Allow additional transitions from one migration_state
to another.

for the gitlab api on the Container Registry client.

in Rest and GraphQL APIs.

This is using the #repository_details endpoint of the gitlab v1 API of
the Container Registry.

Changelog: added

Update Registry EnqueuerWorker to fetch the true
repository status from the registry when making
decisions about what to do with aborted imports.

* add an ending forward slash on the import url
* configure the connection to accept JSON responses
* cleanup the related spec

Introduce a new container registry client class for the endpoints
that are available in the [gitlabcontainer registry API](https://gitlab.com/gitlab-org/container-registry/-/blob/master/docs-gitlab/api.md)

Changelog: added