Improve the Auth - autologin

This turned into more of a project than I expected:

* auto logs in a UNL user if the `unl_sso` cookie was found.
* both the manager and front end implemented their own auth, so I centralized it
* I ran into issues with the testing environment (headers already sent, etc), so I made a mock auth provider for tests

I addressed this here: https://github.com/mfairchild365/UNL_MediaHub/commit/f93055552dc8b73ba2fdf300f5633093c6b115e7