Added tests, info about new feature gate in error message, fixes from review
Added basic e2e test
Added unit tests
Ran hack/update-featuregates.sh
Tolerate updates to existing resources after disabling feature gate
Added feature gate to versioned_kube_features.go
Fixed existing tests
Use PodValidationOptions for validation instead of using feature gate directly
Relaxed validation for allowing zero in prestop hook sleep action