Implement initial audiobook UX (some of which is a bit of a WIP).

- Renamed various components and moved them to src/components.
- Renamed KOTO_PREFERRED_MODEL* to KOTO_PREFERRED_PLAYLIST*
- Renamed koto string utility functions to always be prefixed with koto_utils_string_ for consistency.
- Added configuration options for show / hiding various album information, as well as preferred sort type.
- Changed db schema to reflect various metadata changes (sorry).
- Implemented genre, narrator, year aggregation from KotoTrack to KotoAlbum for use in KotoAlbumInfo and audiobooks.
- Rearchitected our playlist functionality for KotoAlbums to always have an inner KotoPlaylist that is used.
- Added various getters / setters for new koto_album functionality.
- Implement aggregation of KotoAlbum pointer aggregation in the KotoArtist as a GQueue and GListStore instead of GList so we can get all the albums associated with an artist and use the GListStore for the audiobook view.
- Implement some initial album sorting in Artists (more work to do on this front).
- Many improvements to file indexing logic for CD and position detection, various new koto_track_helpers.
- Add new logic for knowing when to hide playlists given we generate them for each Album now.
- Fix missing updates of KotoPlaylist in KotoNav.
- Added playback position to KotoPlayerbar, renamed bar refs to self.
- New Playlist state saving.
- Updated track ticking logic for track in KotoPlaybackEngine.
- Fixed playback position detection in our KotoPlaybackEngine by swapping from GST_FORMAT_DEFAULT to GST_FORMAT_TIME.
- Changed our get_progress to divide by GST_SECOND.
- Fixed missing type checks in various KotoPlaybackEngine functions.

Fixes #13. Fixes #14. Fixes #15.

theme/_disc-view.scss

@@ -10,21 +10,5 @@
 			color: $text-color-faded;
 			margin: 10px 0;
 		}
-
-		& .track-list {
-			& > row {
-				&:not(:active):not(:selected) { // Neither active nor selected, see gtk overrides
-					color: $text-color-bright;
-
-					&:nth-child(odd):not(:hover) {
-						background-color: $bg-primary;
-					}
-
-					&:nth-child(even), &:hover {
-						background-color: $bg-secondary;
-					}
-				}
-			}
-		}
 	}
 }