Feature - Implemented virtual scroll on web (#573)

This PR implemented a virtual scroll on the web, as seen in this article.

[Building the Google Photos Web UI](https://medium.com/google-design/google-photos-45b714dfbed1)

mobile/openapi/test/asset_count_by_time_bucket_response_dto_test.dart

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+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.12
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+import 'package:openapi/api.dart';
+import 'package:test/test.dart';
+
+// tests for AssetCountByTimeBucketResponseDto
+void main() {
+  // final instance = AssetCountByTimeBucketResponseDto();
+
+  group('test AssetCountByTimeBucketResponseDto', () {
+    // String timeGroup
+    test('to test the property `timeGroup`', () async {
+      // TODO
+    });
+
+    // int count
+    test('to test the property `count`', () async {
+      // TODO
+    });
+
+
+  });
+
+}

mobile/openapi/test/asset_count_by_time_bucket_test.dart

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+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.12
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+import 'package:openapi/api.dart';
+import 'package:test/test.dart';
+
+// tests for AssetCountByTimeBucket
+void main() {
+  // final instance = AssetCountByTimeBucket();
+
+  group('test AssetCountByTimeBucket', () {
+    // String timeBucket
+    test('to test the property `timeBucket`', () async {
+      // TODO
+    });
+
+    // int count
+    test('to test the property `count`', () async {
+      // TODO
+    });
+
+
+  });
+
+}

mobile/openapi/test/get_asset_by_time_bucket_dto_test.dart

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+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.12
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+import 'package:openapi/api.dart';
+import 'package:test/test.dart';
+
+// tests for GetAssetByTimeBucketDto
+void main() {
+  // final instance = GetAssetByTimeBucketDto();
+
+  group('test GetAssetByTimeBucketDto', () {
+    // List<String> timeBucket (default value: const [])
+    test('to test the property `timeBucket`', () async {
+      // TODO
+    });
+
+
+  });
+
+}

mobile/openapi/test/get_asset_count_by_time_bucket_dto_test.dart

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+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.12
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+import 'package:openapi/api.dart';
+import 'package:test/test.dart';
+
+// tests for GetAssetCountByTimeBucketDto
+void main() {
+  // final instance = GetAssetCountByTimeBucketDto();
+
+  group('test GetAssetCountByTimeBucketDto', () {
+    // TimeGroupEnum timeGroup
+    test('to test the property `timeGroup`', () async {
+      // TODO
+    });
+
+
+  });
+
+}

mobile/openapi/test/time_bucket_enum_test.dart

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+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.12
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+import 'package:openapi/api.dart';
+import 'package:test/test.dart';
+
+// tests for TimeBucketEnum
+void main() {
+
+  group('test TimeBucketEnum', () {
+
+  });
+
+}