PlaylistHeader: Add a new header to the playlist view
This merge request brings an addition to the playlist view with:
- The addition of a header displaying a bigger artwork cover with buttons more accessible to start the playback regularly and shuffled.
- The
EditController
now also displays the playlist header when the collection is being reordered by the user.
This merge request also brings an adjustment to the playlist sorting criteria:
- The sortModel is properly instantiated in the
playlistModel
instead of being handled by thecollectionModel
.
Closes #1868