[Feature] Update Album Thumbnails to Latest

The feature After adding photos to album, the thumbnail for that album should be set/updated to be the most recent photo, except when a custom thumbnail has already been set for that album. From what I can tell, when setting a custom album "cover"/thumbnail, nothing gets stored in the database to denote that it was manually set (and therefore no way to code against it). Also, upon upload of files for a new album, it looks to take the first photo in the array versus do some comparisons to determine and set to the latest. My thought is that a new column should be created in the albums db table named 'isAlbumThumbnailOverridden'... • Upon a user setting a custom thumbnail, the boolean gets updated to true and the asset id stored alongside it (the latter already exists). • If boolean is set to false (default), then every time new photos get added to an album, the thumbnail gets updated to be the most recent pic (between existing album p…