Plonky2 verifier with Gnark

Since it's currently not possible to directly verify Plonky2 proofs in smart contracts, this problem can be solved by using Gnark. Through a bridge between Gnark and Plonky2 proofs, we generate a program that takes Plonky2 proofs as input and convert them into Gnark-style SNARKs. After this step, we create a smart contract capable of verifying Gnark SNARK proofs.