Deduplicate two different encodings of the same album

[ssssam]

If there is an .mp3 and .flac version of the same album for whatever reason then it is treated as two different albums. It would be better if one 'shadowed' the other and the highest quality encoding was used.

It would be nice to handle this in Tracker itself rather than in Calliope, but that would be tricky to implement as it would have to implement its own heuristics.

A simpler option would be to have cpe musicbrainz annotate figure out the musicbrainz ID for each album. We could then easily spot duplicates.