Description of problem:

See discussion in https://bugzilla.redhat.com/show_bug.cgi?id=2184278

Regenerating repository metadata is dangerous for repositories that use the 'mirror_complete' mirroring policy because it will generate metadata locally, which means your repository is no longer completely mirrored.

The previous BZ addresses this in the web UI. However, you can still regenerate repository metadata for 'mirror_complete' repositories using the API or Hammer. We need to harden the backend code to

1. Refuse to do this for repositories that use complete mirroring
2. When regenerating metadata for CV version repositories, skip repos that use complete mirroring.