118 - Implement shared album feature (#124)

* New features 
  - Share album. Users can now create albums to share with existing people on the network.
  - Owner can delete the album.
  - Owner can invite the additional users to the album.
  - Shared users and the owner can add additional assets to the album.
* In the asset viewer, the user can swipe up to see detailed information and swip down to dismiss.
* Several UI enhancements.

mobile/lib/shared/ui/immich_loading_indicator.dart

@@ -0,0 +1,24 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_spinkit/flutter_spinkit.dart';
+
+class ImmichLoadingIndicator extends StatelessWidget {
+  const ImmichLoadingIndicator({
+    Key? key,
+  }) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      height: 60,
+      width: 60,
+      decoration: BoxDecoration(
+        color: Theme.of(context).primaryColor.withAlpha(200),
+        borderRadius: BorderRadius.circular(10),
+      ),
+      child: const SpinKitDancingSquare(
+        color: Colors.white,
+        size: 30.0,
+      ),
+    );
+  }
+}