Merge pull request #34341 from apprenda/kubeadm-require-root

Automatic merge from submit-queue

kubeadm implement preflight checks

Checks that user running kubeamd init and join is root and will only execute
command if user is root. Moved away from using kubectl error handling to
having kubeadm handle its own errors. This should allow kubeadm to have
more meaningful errors, exit codes, and logging for specific kubeadm use
cases.

fixes #33908

hack/verify-flags/known-flags.txt

@@ -513,6 +513,7 @@ since-seconds
 since-time
 skip-generated-rewrite
 skip-munges
+skip-preflight-checks
 sort-by
 source-file
 ssh-env