Drive ptrace into a wall, prepare for overhaul

I have recently implemented some basic signal handling and it just felt... off. So I gave the RFC a big overhaul with a more scalable system that I believe is much, much better. But since that might end up being a large diff (not too large though, most of the back-end is separated from the front-end luckily), I thought why not merge this working but sub-optimal PR first, as to "flush" the diff and start clean.

To be merged with syscall!39 (merged)