Introduce a server.sls file to handle more global server management tasks

To start, we want to add the webtatic repository for handling the MySQL 5.5 and PHP 5.4 packages (at least). Other repositories can likely go here if they spread across multiple packages.

This may also be where we want to put basic server tools that apply to all servers. vim, curl, etc..
Remove MySQL 5.1.6 and install MySQL 5.5.x

The current CentOS 6.4 image that we're using comes with MySQL preinstalled. This accounts for that by asserting that a few packages are removed before installing MySQL 5.5
Add php-fpm 5.4 to provisioning

This adds the basics for php-fpm. Next we'll need to go through and start adding various modules.
Add php-cli and php-mysql modules
Replacing php54w-mysql with php54w-common for now...

I think I'm going to move to another CentOS repository, as this one seems a bit light on the modules that we should account for. I'd like to use Imagick for processing images rather than GD and the PECL RPM doesn't appear to be avaialble here. This should be the first change tomorrow.