Add sorting by Date added, works exactly the same way as any other sorting rules. Only tracks and albums have this sorting option because an artist can have multiple albums added at a different time (plus media store doesn't provide this info for albums and artists, only tracks. I added it for albums anyway).
Fix a minor glitch with newly set sorting getting reset when reopening the fragment
Closes https://github.com/SimpleMobileTools/Simple-Music-Player/issues/254
Changes: