Add documentation for djblets.configforms.

Review Request #7389 — Created June 5, 2015 and submitted — Latest diff uploaded

Information

Djblets
release-0.9.x
f2e169e...

Reviewers

This improves upon the documentation we already had to cover the
capabilities of the various configform components. It also fleshes out
the return values and arguments for the different functions.

Built the docs and read through them.