previously the loopback configuration was used to talk to the server.
As a consequence a custom API server was unable to talk to the root API server.
Kubernetes-commit: 074544b3b024156e4ce91de5778281dbe1b47a72
ApplyTo adds the admission chain to the server configuration the method lazily initializes a generic plugin
that is appended to the list of pluginInitializers.
apiserver.Config will hold an instance of SharedInformerFactory to ensure we only have once instance.
The field will be initialized in apisever.SecureServingOptions
Kubernetes-commit: 8cea69aa9812d6627ebdfa4f8b9c1d7624a8f3f5
p0lyn0mial