This adds documentation on configuring Bazaar, ClearCase, CVS, Git,
Mercurial, Perforce, and Subversion repositories. It goes into the
various setup options for each type and provides a complete walkthrough
on how to get set up, from installing dependencies to configuring fields
to the various authentication and conncetion options (where appropriate).
This replaces the old and very basic documentation we had before.

These docs do not cover setting up hosting services yet. That will be
done separately.

Built the docs and read through. Checked links and setup instructions

for accuracy.