We need to deploy puppetDB, so we need to create a role::puppet::puppetdb manifest that can set up:

• puppetdb should be installed via the package define; for now we'll backport a puppetDB 2.3 deb from the puppetlabs repositiories, that can be changed to a different provider if we see fit
• a postgres instance should be running on the machine, and accept md5 auth and SSL connections.
• Postgres replication should go from the master to the slave as defined in the role.
• puppetdb on both master and slaves should connect to the master's postgres instance