Add ability to create required registry mirror repositories

As mentioned in #1629, it would be nice to be able to create the required repositories for the user instead of fail with an access denied when they don't exist and have the user create them manually. This implementation may have to registry specific so it might warrant a new command.

Start by reading issue #1629 and tracing how registry mirror repositories are currently handled. Define the registry-specific behavior or new command needed to create missing repositories, and confirm completion when setup no longer fails with access denied and the required repositories are created for the user.

Written by the indexing model from the issue text.