Add verifier contract using constantine library

[kkirkov]

No description provided.

[EmilIvanichkovv]

Minimize the presence of duplicate files.

[mratsim]

Multipairings can optimize speed by almost 2x.

[mratsim]

It would be almost 2x faster if multipairings were used there and the result checked for one:

with the signature

func pairing*[N: static int, C](
       gt: var Fp12[C],
       Ps: array[N, ECP_ShortW_Aff[Fp[C], G1]],
       Qs: array[N, ECP_ShortW_Aff[Fp2[C], G2]]) =

from https://github.com/mratsim/constantine/blob/d69c7bf/constantine/math/pairings/pairings_generic.nim#L16C1-L22
forwarding to https://github.com/mratsim/constantine/blob/d69c7bf/constantine/math/pairings/pairings_bn.nim#L178-L181

prf.a needs to be negated beforehand because:

e(prf.a, prf.b) = e(vk.alpha, vk.beta).e(preparedInputs.data, vk.gamma).e(prf.c,vk.delta)

is equivalent to

e(-prf.a, prf.b).e(vk.alpha, vk.beta).e(preparedInputs.data, vk.gamma).e(prf.c,vk.delta) = 1

see BLS signatures: https://github.com/mratsim/constantine/blob/d69c7bf/constantine/signatures/bls_signatures.nim#L123-L127

[kkirkov]

Thanks for the advice! #184
Gas usage:
using Bncurve - around 1695k
using Constantine(no multipairings) - around 1400k
using Constantine(with) - around 870k

[mratsim]

I'm surprised the dash is accepted