Suggested teuthology priority

For developers submitting jobs using teuthology, we now have recommendations on what priority level to use: https://docs.ceph.com/docs/master/dev/developer_guide/#testing-priority -- Patrick Donnelly, Ph.D. He / Him / His Senior Software Engineer Red Hat Sunnyvale, CA GPG: 19F28A586F808C2402351B93C3301A3E258DD79D