[zkMemory] Use rayon in zkMemory and polynomial evaluation

[chiro-hiro]

Rayon and Tokio could be used to improve these kind of code.

        // Evaluate the values p_i(x_i) for i=1,2,...,n and add to the transcript
        for (poly, point) in polynomial_list.iter().zip(&points_list) {
            transcript
                .write_scalar(eval_polynomial(poly, *point))
                .unwrap();
        }