Feature enhancement: Hyperlink to DB entry where no genre is found.

[tandy-1000]

It would be useful to be able to produce the Musicbrainz / Last.fm / Redacted link for items where a genre wasn't found, so that the user could submit genres to the relevant sources to improve the databases.

It could look like this:

No genres found (34):
  /music/Baltra & Park Hye Jin/Ahead Of Time
  https://musicbrainz.org/release-group/6c370f9a-829a-45f3-bb6f-80c3ccb027d7