Rely on another algebraic hash function

[Nashtare]

We currently rely on rescue_63_14_7 for hashing the transaction in our modified Schnorr signatures.
It represents currently 25% and could be brought down to ~11/12% by using Poseidon for instance, at the cost of a light increase in the AIR program (we could still use Rescue for the Merkle authentication paths and replace only the signature hashing).