Remove legacy ContainerRepository replication

This issue is a part of "Geo: Move container registry to self-service framework" effort. This is similar to what we always do when we migrate data to a new Geo SSF framework, see !85219 (merged). When we're sure that it works fine we remove the old code.

Apart from the obvious things, we need to pay attention to these things:

• mark_synced_atomically method had to be addressed. We don't use it in SSF.
• ee/app/models/geo/container_repository_registry.rb#registry_consistency_worker_enabled? can be removed.
• Remove “### Remove it after data migration” labels.
• ee/app/workers/geo/container_repository_sync_dispatch_worker.rb. Can be removed.
• Remove load_container_registry_data method.
• container_repositories_max_capacity parameter has to be removed or modified accordingly. (Created issue #372444 (closed))
• ContainerRepositorySyncDispatchWorker Can be removed.
• Geo::ContainerRepositoryReplicator is enabled in ee/spec/helpers/ee/geo_helper_spec.rb can be removed.
• Update ee/spec/models/container_registry/event_spec.rb is not needed anymore
• Geo::ContainerRepositoryUpdatedEvent related stuff.
• Address !100750 (comment 1135401703)