Android Auto: Update sort order and correction of small defects

Description

This MR is a roll-up of several small modifications:

• Simplified logic in ArtworkProvider.getPlayAllImage and updated "Play All" image track listing
• Resolved a special-case issue for a single valid artwork image after an invalid image not showing correctly
• Play all by genre plays in order of each album first, then by tracks in the album
• Changed default return order of Album and Artist classes.
  _(Sorting tracks in an album by album returned a warning and reverted to sort by default order anyway)_
• Removed checksum from playlist key, as the new scheme adds media ids automatically

Motivation and Context

This is a follow-on to !971 (merged) to sort the content displayed throughout the Android Auto menus in a consistent manner. The order of tracks queued by "Play All" is in order of appearance. The ArtworkProvider was updated to match the "Play All" image with the adjacent art in the menu (also with playback order). I opted to update the default return results from the media library rather than specify the desired sort order, e.g. getAlbums(Medialibrary.SORT_ALPHA, false) on each call. I thought making the defaults more sensible was a simpler way to go.

How Has This Been Tested?

I fully built an updated media library to confirm the changes work as expected.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have read the CONTRIBUTING section of the README document.