Integrate Symfony Security Component

[midnightLuke]

The security portion of the app is extremely light (lock out unwanted guests with basic authentication), but it would still be better to integrate the security component if we can rather than rely on custom code in the app for this.

The other advantage to this is the opportunity to provide other methods of authentication, for example if a larger organization would like to use LDAP or authenticate against an external service the security component can so this with a little work.