Switch eqiad's ms-fe & ms-be to Swift

Ceph pilot is done, reusing the hardware for a new Swift cluster. This
copies the pmtpa setup as-is. Many improvements could be done but let's
defer those for after the cluster is built.

This changes:
  - autoinstall entries
  - role classes
  - site.pp to use the above role classes

Change-Id: I91d2eaf850087d3488d03cc7c30d7efd2c18ac9a