Adds OS flavors

Note: this is expected to fail circleci tests because there are changes to the cookbooks to accommodate the OS's added in the yaml. This passed a hot test locally.

This adds CentOS 6, RHEL 6, Ubuntu 14.04, and Debian 7 support. There are a ton of changes, most of them are in upstream cookbooks. In particular for my additions, the tests were expanded, the firewall had ipv6 rules removed for the MySQL rules (since there's not an ipv6 service net), an additional recipe to set up the virtual host properly (because the drupal cookbook is using node[:fqdn] for Servername, which isn't legal with Apache 2.4 in our case), and a recipe to get the php-dom package installed and ports.conf setup for RHEL/Cent to make it compatible.