Automatic merge from submit-queue (batch tested with PRs 44019, 42225)
federation: Fixing runtime-config support for federation-apiserver
Fixes https://github.com/kubernetes/kubernetes/issues/42587
Ref https://github.com/kubernetes/kubernetes/issues/38593
Fixing the broken `--runtime-config` flag support in federation-apiserver. Fixing the bugs and using it to disable batch and autoscaling groups. Users can enable them by passing `--runtime-config=apis/all=true` to federation-apiserver.
~This also includes a bug fix to kube-apiserver registry that allows users to disable api/v1 resources~
cc @kubernetes/sig-federation-pr-reviews