This was originally going to be just the testsuite but I kinda just
documented all of them.
I am tired of us not documenting these. This is a starting point to
producing an actually good index. I would like to enforce it in a
pre-commit hook eventually that we document all environment variables
used in Lix itself, even if it is terse dev facing docs.
This is full of a bunch of TODOs caused by auditing code. They should
probably be done at some point.
Change-Id: I7c0d3b257e19bae23d47d1efbd7361d203bccb0e
59b5965bbf