Removes any reference from the registry gcr.io/kubernetes-e2e-test-images in
kubernetes/kubernetes, replacing it with k8s.gcr.io/kubernetes-e2e-test-images.
In some cases, the images had to be updated since a few things have changed since
their original implementation, most notably being the fact that some of the images
have been centralized into the agnhost image.
Co-Authored-By: Claudiu Belu <cbelu@cloudbasesolutions.com>