Convert from CSS to SCSS. Make a multitude of refinements to styling along the way.

Remove unused glade UI file. Added CSS classes to various components. Fix some alignment issues. Renamed our albums_strip to favorites_list.

Implement recursive file parsing in KotoIndexedAlbum with the intent of using it for "discs" / CD, useful for albums like Foo Fighters: In Your Honor that have 2 or more CDs. Still need to work on refining this further.

Add stub function in our album view for a planned separation of the track listing so we can do it based on discs and other depth-of-3 sub-folders.

theme/meson.build

@@ -0,0 +1,21 @@
+sassc = find_program('sassc', required: true)
+
+theme = custom_target('Theme generation',
+	input: 'main.scss',
+	output: 'style.css',
+	command: [
+		sassc,
+		[ '-a', '-M', '-t', 'compact' ],
+		'@INPUT@', '@OUTPUT@',
+	],
+	depend_files: files([
+		'pages/_music-local.scss',
+		'_button.scss',
+		'_vars.scss',
+		'_expander.scss',
+		'_player-bar.scss',
+		'_primary-nav.scss',
+		'_track-item.scss',
+	]),
+	build_by_default: true,
+)