Cleanup code, and refactor tests that still use Rugged. After this, there should
be no Rugged code that access the instance's repositories on non-test
environments. There is still some rugged code for other tasks like the
repository import task, but since it doesn't access any repository storage path
it can stay.
Remote mirrors only get created when the URL changes, However, during the GCP
migration, the remote mirror did not get created automatically. Plus, there's
no guarantee someone restoring a repository from backup would have this
remote. We now add the remote each time we attempt to fetch from the
repository.
This works because Gitaly doesn't throw up an exception or error if the
remote already exists:
https://gitlab.com/gitlab-org/gitaly/issues/1317
In the future, we should attempt to add if the remote doesn't exist:
https://gitlab.com/gitlab-org/gitaly/issues/1316Closes#50562
