remove professor from DNS (decom)

per RT #6269 the migration has been completed
and it can be nuked

also see Change-Id: I1aeeb9d625debe0465626b2791cd2e3bc522239e
which removes it from site.pp

merge depending on the correct order of other needed decom
steps like revoking keys, wiping etc

Change-Id: I90b68c4ae6d89f758863b5057f0d2e63108e5adb