This pulls in the register xml, rnn, decode tools, and afuc (ie. everything that depends on the xml) into mesa. And adds equivalent CI to what I had setup in the gitlab envytools tree.
I haven't yet sorted out syncing back to the envytools tree (I guess some sort of cron job would do the trick?)
I setup cffdump and crashdec to be installed (if tools are built, and dependencies are found), but I guess the rest of the tools are niche enough to not bother installing. But I could be convinced either way. Possibly we should rename cffdump/crashdec to something in the "fd" namespace, like fdperf. (fddump/fdcrashdec??)
There is still some room to de-duplicate a little, in particular not having two copies of the disassemblers.. but I haven't sorted out yet how that would work, since they are slightly different as a result of their different requirements. That might come later.