Automatic merge from submit-queue (batch tested with PRs 41857, 41864, 40522, 41835, 41991)

kubeadm: update token separator to '.'

**What this PR does / why we need it**: From SIG meetings, it was agreed upon to have '.' be the separator for tokens. This PR updates that. 

**Special notes for your reviewer**: /cc @luxas @jbeda

**Release note**:
```release-note
NONE
```