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/modules/sharing/models/shared_asset.model.dart

@@ -0,0 +1,50 @@
+import 'dart:convert';
+
+import 'package:immich_mobile/shared/models/immich_asset.model.dart';
+
+class SharedAssets {
+  final ImmichAsset assetInfo;
+
+  SharedAssets({
+    required this.assetInfo,
+  });
+
+  SharedAssets copyWith({
+    ImmichAsset? assetInfo,
+  }) {
+    return SharedAssets(
+      assetInfo: assetInfo ?? this.assetInfo,
+    );
+  }
+
+  Map<String, dynamic> toMap() {
+    final result = <String, dynamic>{};
+
+    result.addAll({'assetInfo': assetInfo.toMap()});
+
+    return result;
+  }
+
+  factory SharedAssets.fromMap(Map<String, dynamic> map) {
+    return SharedAssets(
+      assetInfo: ImmichAsset.fromMap(map['assetInfo']),
+    );
+  }
+
+  String toJson() => json.encode(toMap());
+
+  factory SharedAssets.fromJson(String source) => SharedAssets.fromMap(json.decode(source));
+
+  @override
+  String toString() => 'SharedAssets(assetInfo: $assetInfo)';
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+
+    return other is SharedAssets && other.assetInfo == assetInfo;
+  }
+
+  @override
+  int get hashCode => assetInfo.hashCode;
+}