Automatic merge from submit-queue (batch tested with PRs 65582, 65480, 65310, 65644, 65645). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
allow enabling kubelet serving certificate rotation via flag
allows the server rotation feature to be exercised via flags as well as config file
```release-note
NONE
```
ecf2c0e44b