Add capstone backend

I've added/extended capstone as a backend to actually disassemble instructions for all of the existing architectures rather than pull strings out of the qemu dump (not that capstone is smarter than QEMU in this regard, but we'll be able to get a "smarter" instruction representation on the frontend)

The frontend has the exact same behavior until we discuss what behavior you want wrt registers/instructions.

After that the next stage will be to use capstone to disassemble not just memory from the traces but instructions out of the original binary for the static portion of QIRA. (in case instructions were missed)