Add keys and script for puppet over ssh

In anticipation of driving puppet over ssh, we need keys on the hosts
and the scripts on the master. Don't turn them on yet, because we want
to be able to do some by-hand testing of the mechanism.

Change-Id: I2c353777e2f8fb5a2e733ce405ba40427ce901e5
Merge "Add keys and script for puppet over ssh"