add Jellyfin integration

src/components/services/widgets/service/jellyfin.jsx

@@ -0,0 +1,6 @@
+import Emby from "./emby";
+
+// Jellyfin and Emby share the same API, so proxy the Emby widget to Jellyfin.
+export default function Jellyfin({ service }) {
+  return <Emby service={service} title="Jellyfin" />;
+}