Add contentqa

This branch adds playbooks and roles for content QA hosts, which each have a large stack of services.  They have one each of the usually-clustered services, BigCouch and Elasticsearch.

There are various changes and fixes to account for this.  The added roles are not intended to be used on VMs, and the existing "development" playbooks should not touch them.

The main thing that I see possibly affecting the development VMs is the change to the PostgreSQL database's encoding, to account for the new default server locale of en_US.UTF8.  This needs to be tested in the development environment.

Should we specify the SES hostname using a template? This hardcodes this to the `us-east-1` region.