* Adds an env variable to .env to turn on dev mode
* Uses the inbuilt django auth rather than saml when in dev mode
* For laziness, re-uses the admin login form for the non-admin login
make_dev_container now comes up ready to be logged into by any
user. No non-admin users are preconfigured; but you can add one at
http://localhost:28000/admin/auth/user/add/, log out, and then hit
http://localhost:28000/ to log in as the new user.
