refactor(mobile): reworked Asset, store all required fields from local & remote (#1539)

replace usage of AssetResponseDto with Asset

Add new class ExifInfo to store data from ExifResponseDto

mobile/lib/utils/builtin_extensions.dart

@@ -0,0 +1,11 @@
+extension DurationExtension on String {
+  Duration toDuration() {
+    final parts =
+        split(':').map((e) => double.parse(e).toInt()).toList(growable: false);
+    return Duration(hours: parts[0], minutes: parts[1], seconds: parts[2]);
+  }
+
+  double? toDouble() {
+    return double.tryParse(this);
+  }
+}