Retire cache01 and cache-02 machines

These machines were set up as caching reverse proxies for the Pantheon Drupal blog hosting to cut down on bandwidth costs.

Since the new blog is now hosted on TPO web mirror infrastructure, we should consider either retiring or repurposing these two machines.

1. announcement
2. nagios
3. stop the VM in advance:
4. retire the host in fabric
5. remove from LDAP with ldapvi
6. power-grep
7. remove from tor-passwords
8. remove from DNSwl (not a mail machine)
9. remove from docs
10. remove from racks (VMs only)
11. remove from reverse DNS