In which I fiddle around for some stronger dev utilities and add the most basic CRUD for user accounts

I've added some utilities for development and cleaned up a bit of hackathon cruft.
I've also added the most basic of basic CRUD end-points for manipulating user accounts.  It will surely start doing more soon, but this is a fine place to start.

These two things really should have been two different pull requests (it's best to keep these things short.)

You can see the API in use in the unit tests (backend/tests/users/users_tests.py) which should hopefully provide good working examples of how to interact with the API.

@maiamcguinness @wilhow