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/models/user_info.model.dart

@@ -0,0 +1,60 @@
+import 'dart:convert';
+
+class UserInfo {
+  final String id;
+  final String email;
+  final String createdAt;
+
+  UserInfo({
+    required this.id,
+    required this.email,
+    required this.createdAt,
+  });
+
+  UserInfo copyWith({
+    String? id,
+    String? email,
+    String? createdAt,
+  }) {
+    return UserInfo(
+      id: id ?? this.id,
+      email: email ?? this.email,
+      createdAt: createdAt ?? this.createdAt,
+    );
+  }
+
+  Map<String, dynamic> toMap() {
+    final result = <String, dynamic>{};
+
+    result.addAll({'id': id});
+    result.addAll({'email': email});
+    result.addAll({'createdAt': createdAt});
+
+    return result;
+  }
+
+  factory UserInfo.fromMap(Map<String, dynamic> map) {
+    return UserInfo(
+      id: map['id'] ?? '',
+      email: map['email'] ?? '',
+      createdAt: map['createdAt'] ?? '',
+    );
+  }
+
+  String toJson() => json.encode(toMap());
+
+  factory UserInfo.fromJson(String source) => UserInfo.fromMap(json.decode(source));
+
+  @override
+  String toString() => 'UserInfo(id: $id, email: $email, createdAt: $createdAt)';
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+
+    return other is UserInfo && other.id == id && other.email == email && other.createdAt == createdAt;
+  }
+
+  @override
+  int get hashCode => id.hashCode ^ email.hashCode ^ createdAt.hashCode;
+}