Use IPA

[marcbeunardeau88]

For now the proof is generated using KZG and folding a lot of different proofs.
We need to replace folding with single proof generation using the Pasta IPA proof system (similar to initial zkVM prototype prover here)
At the same time we can reorganise the poly commitment with KZG and IPA submodules. We must abstract the srs and the commitments. Once we have more generic code, we instantiate with IPA.