Cleanup naming & order in admin controller

I imagine that a lot of the admin routes need to either disappear into 1-page-app-wonderland, or be moved onto the API, but at least this makes it easier to see what we're working with.

I know this might conflict with other PRs so prob won't merge straight away.

 There seemed to be no convention or order to the functions in the admin controller, so I have:
 - organised them
 - reordered them
 - added a small doc-block
 - reordered some routes
 - updated tests accordingly