Add GTK application implementation

data/data.go

@@ -0,0 +1,32 @@
+package data
+
+import (
+	_ "embed"
+)
+
+//go:embed ui/window.ui
+var WindowXML string
+
+//go:embed ui/shortcuts-dialog.ui
+var ShortcutsDialogXML string
+
+//go:embed ui/connection-panel.ui
+var ConnectionPanelXML string
+
+//go:embed ui/server-panel.ui
+var ServerPanelXML string
+
+//go:embed ui/cover-panel.ui
+var CoverPanelXML string
+
+//go:embed ui/playlist-panel.ui
+var PlaylistPanelXML string
+
+//go:embed ui/album-headerbar.ui
+var AlbumHeaderbarXML string
+
+//go:embed ui/library-panel.ui
+var LibraryPanelXML string
+
+//go:embed gtk.css
+var MainCSS string