Remove useBandAsAlbumArtist preference. 

As useBandAsAlbumArtist has been mostly obsoleted by the bandAsArtist
preference and only been called in some remote places, I'm replacing it
with bandAsArtist etc. in this place
When browsing by albums, display the full list of album artists, not
only the randomly picked one from albums.contributor.

This needs some refinement and probably a preference to disable the
change, as it comes at a cost of performance.