feat(poly): impl fft/ifft methods

The fft (Fast Fourier Transform) and ifft (Inverse Fast Fourier Transform) are algorithms used to compute the discrete Fourier transform (DFT) and its inverse efficiently

Also within this task we have to realize finding a cyclic group of a certain size

// axiom halo2_proofs:src/poly/domain.rs
pub struct EvaluationDomain<F: Field> {
      n: u64, //n =2^k
      k: u32, 
      omega: F,  // fft {w,w^2,w^4,...,1}
      omega_inv: F, // ifft  {w',w'^2,w'^4,...,1}
      ifft_divisor: F,

      // not sure
      t_evaluations: Vec<F>,
      // Recursive stuff
      // not sure
      fft_data: HashMap<usize, FFTData<F>>,
  }

Implement or import fft/ifft methods which will be used later

snarkify / sirius

feat(poly): impl fft/ifft methods #258