Fast Mersennes Prime Field

[MauroToscano]

• [x] Implement the 32 bit Mersennes Prime Field, F = 2^31 - 1, with an efficient backend. Bench it against the same field implemented with montgomery backend
• [ ] Add a differential fuzzer against a Montgomery implementation
• [ ] Implement the degree 4 field extension

It's recommended for new collaborators to only do the first task, since the code has no examples of field extensions for FRI

The last task needs discussion on how would be the best approach to implement it, API wise.

For references, see:

Reed-solomon over circle fields Plonky 3 implementation