Add job to delete ceph admin keys

[alram]

This will delete the secrets for mon.keyring, bootstrap-{osd,mds,rgw}, client.admin, and the admin secret for the storageclass. @rootfs @dmick not sure "admin" is the best name for all that. Any suggestion?

[alram]

Just wanted to do a last sanity check. Re-opening

[rootfs]

/lgtm