Always provide tags from Mopidy-Local if the track is indexed in the database

[NyaomiDEV]

Using HUGE playlists on Mopidy comes at a huge expense of time because the File bundled extension has to scan tags TWICE, which is slow. Please, consider adding an option to provide indexed tags to File; this way playlists should be a little bit faster to use.

Either this or #4 should be fine though