Add an extension for managing

Review Request #5554 — Created Feb. 26, 2014 and submitted — Latest diff uploaded


This provides a new authentication backend that generates suitable
usernames and passwords. Users will get a message on the login page as
to what username they should use. Upon logging in, they will be placed
in whatever configured review groups are provided on the authentication
settings page.

There's also a couple management commands for maintaining the server.
One for resetting the state of the demo server (which we can call
nightly), and one for dumping the database (similar to dumpdata, but
excludes anything we don't want to dump).

Been testing this locally with the demo server work I've been doing.
I saw the generated username/password on the login page, and could
successfully log in.

I reset the state of the demo server, logged in again, and saw all the
review requests in a clean state, with updated timestamps.

I've been using the dump-demo-data command for generating fixtures to
reset to.