One of the big things the RBTools docs have lacked was a complete

breakdown of all available .reviewboardrc options. We pretty much left

all but the main ones as an exercise to the reader. The best we offered

was a reference to an option name in the docs for command line options.
This change updates our user and repository docs to list all options

that are available, with type information, examples, and relevant

commands.
I've taken a best guess at where each option should go. Some are likely

to be pretty user-specific, and so those have been placed in the user

docs. The rest live in the repository docs.
Each option makes use of a new ReST crossref type called rbtconfig.

This can be used to reference a particular config option no matter where

it is in the docs. The generated list of option docs now use this to

link to the appropriate config docs.

Built the docs. Checked for broken errors and links.