Automatic merge from submit-queue
Allow secure access to apiserver from Admission Controllers
* Allow options.InsecurePort to be set to 0 to switch off insecure access
* In NewSelfClient, Set the TLSClientConfig to the cert and key files
if InsecurePort is switched off
* Mint a bearer token that allows the client(s) created in NewSelfClient
to talk to the api server
* Add a new authenticator that checks for this specific bearer token
Fixes#13598
* Allow options.InsecurePort to be set to 0 to switch off insecure access
* In NewSelfClient, Set the TLSClientConfig to the cert and key files
if InsecurePort is switched off
* Mint a bearer token that allows the client(s) created in NewSelfClient
to talk to the api server
* Add a new authenticator that checks for this specific bearer token
Fixes#13598