to avoid unnecessary blob re-uploads.
Cross repository mount from particular repo will most probably fail if
the user pushing to the registry is not the same as the one who pulled
or pushed to the source repo.
This PR attempts first to cross-repo mount from the source repositories
associated with the pusher's auth config. Then it falls back to other
repositories sorted from the most similar to the target repo to the
least.
It also prevents metadata deletion in cases where cross-repo mount fails
and the auth config hashes differ.
Signed-off-by: Michal Minář <miminar@redhat.com>
