Enhance testing and integration for checkbox-list custom field

- Updated Gitea workflow to trigger on pushes to the master branch and refined job configurations for testing and E2E processes.
- Added Jest and Playwright configurations for integration and E2E testing.
- Introduced new checkbox-item API with corresponding controller, service, and routes.
- Created integration tests for the checkbox-list functionality, ensuring proper handling of required fields and default values.
- Updated package.json and package-lock.json to include necessary dependencies for testing.

playground/src/api/checkbox-item/routes/checkbox-item.ts

@@ -0,0 +1,7 @@
+/**
+ * checkbox-item router
+ */
+
+import { factories } from '@strapi/strapi';
+
+export default factories.createCoreRouter('api::checkbox-item.checkbox-item');