Static refactoring

Dependent on #19

Extend static file refactoring to central server.  
* Delete all distributed server static files
* Move app-specific static files to `{app}/static/[css, images, js]/{app}`
* Move common files to `/static`
* Use `collectstatic` to gather central, distributed, and shared files into the `/code/static` folder, which the server uses.

Note:
* Until #18 is resolved (should be Sunday), this will require running `collectstatic` manually before the central server would show any static files.