Automatic merge from submit-queue (batch tested with PRs 41980, 42192, 42223, 41822, 42048)
Modified kubemark startup scripts to restore master on reboot
Fixes#41735
As discussed in the issue, modified the scripts to satisfy the conditions of restoring master env, running non-idempotent operations only for the first time and persist important data like pki/auth files on a PD.
Also attached `start-kubemark-master.sh` as startup-script metadata to master instance (on GCE) so that it is called automatically on each boot.
cc @kubernetes/sig-scalability-misc @wojtek-t @gmarek
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