Add class to handle welcome rsa key
Add class to handle welcome rsa key

Currently this functionality lives internally
on modules using gerrit, and will be good if that
can be isolated on a class of the module.

Change-Id: I318e09ddbaedb2459b47e340a1826123a0dba52b

dhiana/puppet-gerrit,dhiana/puppet-gerrit,dhiana/puppet-gerrit