Automatic merge from submit-queue (batch tested with PRs 42835, 42974)
remove legacy insecure port options from genericapiserver
The insecure port has been a source of problems and it will prevent proper aggregation into a cluster, so the genericapiserver has no need for it. In addition, there's no reason for it to be in the main kube-apiserver flow either. This pull removes it from genericapiserver and removes it from the shared kube-apiserver code. It's still wired up in the command, but its no longer possible for someone to mess up and start using in mainline code.
@kubernetes/sig-api-machinery-misc @ncdc
`/var/run` is not world-writable on my OSX 10.11.x setup, so tests that
standup a secure apiserver fail with the default cert dir. Use a
tempdir instead.
* 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