feat: Add build info and localization for entry app

- Introduced buildinfo.json5 to enable impeller feature.
- Added Chinese localization strings in string.json for module description and entry ability.
- Created Ability.test.ets for unit testing of ability functionalities.
- Implemented List.test.ets to run the ability tests.
- Developed TestAbility.ets to manage test execution and lifecycle events.
- Created Index.ets as a testability page with UI components.
- Added OpenHarmonyTestRunner.ts for managing test execution in OpenHarmony.
- Defined module.json5 for entry_test module configuration.
- Established color.json and string.json for base resources.
- Included icon.png for the test module.
- Created test_pages.json to define testability page sources.
- Configured hvigor and oh-package.json5 for project setup.
- Updated pubspec.yaml and related files to downgrade Dart SDK to 3.11.0 and adjust dependencies.
- Added PowerShell script to enable OpenHarmony Flutter toolchain.
- Updated multiple package pubspec.yaml files to align with Dart SDK version 3.11.0 and adjust dependencies accordingly.

app/ohos/hvigorfile.ts

@@ -0,0 +1,8 @@
+import path from 'path'
+import { appTasks } from '@ohos/hvigor-ohos-plugin';
+import { flutterHvigorPlugin } from 'flutter-hvigor-plugin';
+
+export default {
+    system: appTasks,  /* Built-in plugin of Hvigor. It cannot be modified. */
+    plugins:[flutterHvigorPlugin(path.dirname(__dirname))]         /* Custom plugin to extend the functionality of Hvigor. */
+}