RISC-V machine Extract all lookups / permutations into machine calls

[georgwiese]

Any lookup (e.g. pre-computed tables, range checks, etc) should be a machine call. This has two advantages:

• We benefit from VadCop: The extracted machine just contains fixed columns of a very particular size, and the machine calling it can potentially be smaller.
• We can do Plonky3 proofs for our RISC-V machine, because (i) Plonky3 doesn't come with a native lookup / permutation implementation and (ii) machines are (eventually) connected via a bus argument, which only requires the backend to support challenges.