UI To manage artists, albums, tracks

See #689 (closed)

• Artists
• Albums
• Tracks

This MR includes:

• A UI to browse Artists/Albums/Tracks (for users with the library permission):
• A UI to delete those entities (either one by one or in batch, as we can do with uploads)
• Links to the admin ui on artist, album and track pages
• Moved all many buttons that were displayed and artist, album and track pages to a dropdown

Dropdown on album page

Album admin detail

Album admin list

The ui for artists and albums is similar.