Copy auth plugin to client-go repo #33334
@krousey this PR is ready. PTAL.
The commit "remove special clientrepo code from main repository gcp plugin" maybe the a little mysterious. Because our e2e test uses client-go, I used to add the special initialization code for auth plugin for client-go. It's not needed anymore. Because client-go/kubernetes/clientset.go will initialize the auth plugin for client-go.
Please let me know if there are other non-obvious changes. Thanks!
rename plugin/pkg/client/auth/plugins.go package name to auth add the plugin import line in client-gen update import_known_versions for release_1_5 clientset change copy.sh