refactor(server): download assets (#3032)

* refactor: download assets

* chore: open api

* chore: finish tests, make size configurable

* chore: defualt to 4GiB

* chore: open api

* fix: optional archive size

* fix: bugs

* chore: cleanup

mobile/openapi/test/download_response_dto_test.dart

@@ -0,0 +1,32 @@
+//
+// 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 DownloadResponseDto
+void main() {
+  // final instance = DownloadResponseDto();
+
+  group('test DownloadResponseDto', () {
+    // int totalSize
+    test('to test the property `totalSize`', () async {
+      // TODO
+    });
+
+    // List<DownloadArchiveInfo> archives (default value: const [])
+    test('to test the property `archives`', () async {
+      // TODO
+    });
+
+
+  });
+
+}