Implements Client Management Endpoints

We already had the R of CRUD, this adds the other 3. The 3 new endpoints require an oauth token with the scope `oauth`. Yo dawg, I heard you like oauth?

@rfk r?
@vladikoff you should take a look and see if there's something I've forgotten that the console will need.

fixes #60 
Ah, I assumed there would only be one strategy ever active. So if/when we switch from bearer tokens, I could adjust the `AUTH_STRATEGY` constant in `auth.js`, and all the other files would continue to use the blessed strategy.