Ansible setup for provisioning production web servers

What is covered by this PR:
* Provisioning of 2 cloud servers in IAD and 2 cloud servers in DFW.
* Provisioning of 1 cloud load balancer in DFW with the 4 cloud servers above as nodes.
* Load balancer listens to HTTP requests on port 80.
* Cloud servers have nginx installed, configured and running.
* Static site content should be placed under `/var/www/html/developer.rackspace.com/` on each cloud server.
* Instructions on how to run Ansible provisioning script can be found in `deploy/README.md`.

What is NOT covered by this PR:
* Creation of a user on each cloud server that Jenkins can use to auto-push static site content.
* Elastic Search setup. I think it might be better to treat this as its own application (possibly in its own GitHub repo even) fronted by a CLB so the web site can access its REST API. Thoughts?