cleanup/refactory: Implement and refactor e2e tests for 'alpha genera…

…te' command

- Added comprehensive end-to-end tests for the 'generate' command.
- Ensured proper validation of the 'PROJECT' file after project initialization and regeneration.
- Verified correct handling of multigroup layouts, Grafana, and DeployImage plugins.
- Refactored the test structure to align with existing patterns used in other tests.
- Improved maintainability and test coverage to support future growth and more scenarios.

test/e2e/alphagenerate/e2e_suite_test.go → test/e2e/generate/e2e_suite_test.go

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package alphagenerate
+package generate
 
 import (
 	"fmt"