Port to GTK4, start implementation of Local Music view, Artist and Album Views.

data/style.css

@@ -1,3 +1,11 @@
+window {
+	background-color: #2e2e2e;
+}
+
+headerbar, .player-bar {
+	background-color: #1d1d1d;
+}
+
 .primary-nav > .frame > box >.koto-button > box {
 	padding: 10px 0;
 }
@@ -19,3 +27,11 @@
 .expander-header label {
 	font-size: large;
 }
+
+.page-music-local .artist-list {
+	background-color: #1d1d1d;
+}
+
+.page-music-local row {
+	padding: 10px;
+}