First cut at conversion from LaTeX to mdbook for the CHERI C/C++ guide.

[rwatson]

There are known nits including with compiler warning formatting and equations.

Not yet a merge candidate.

[rwatson]

Reviewer note: With the exception of the above-mentioned note about equation and compiler warning formatting, this is believed to be a fairly complete and very literal conversion from LaTeX to mdbook. In some places I’ve had to make minor content changes to reflect the new format (e.g., the reading section). My main worry right now is that I’ve dropped or duplicated content as a result of breaking things out into separate files, hooking them up, etc., so additional eyes would be welcome.

I’ll poke the formatting on the above a bit more tonight, but would love to get this live sooner rather than later so that we can facilitate future changes, as hopefully mdbook will make for a better living document format. Also, it will now be easy to link directly to sections of the report when answering questions in Slack, in the FAQ, etc.

[brooksdavis]

The presence of src/impact/README.md.bak breaks mdbook serve