Add media service to image rewriting

Waiting on a NGINX config change for this to go through.
Images from the media service need to be rewritten with `/media` prefixed as discussed with @phamann.

![Cameras](http://gifshost.com/012012/1327341659_lightning_caught_on_camera.gif)
probably want this to be `val imageHosts = ...`.

If it is a function (`def`) a new list gets created every time it is called.