Allow gitlab backup restore to restore one repo or a group of repos

Currently you can create a backup by type and restore that:

• db (database)

• uploads (attachments)

• repositories (Git repositories data)

• builds (CI job output logs)

• artifacts (CI job artifacts)

• lfs (LFS objects)

• registry (Container Registry images)

• pages (Pages content)

but there is no way to restore a specific repo from a backup. Seems like it might be a good feature to allow restoring on a repo or group basis. This was brought up in a customer call.

ZD: https://gitlab.zendesk.com/agent/tickets/69248