Implement fast polynomial interpolation for bn254 base field

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For pufferfish, we have to interpolate a very large polynomial over bn254 base field. Crypto3's polynomial interpolation is slow (basic Lagrange) or incompatible with the field we are using (FFT), so we need to either optimize Lagrange or implement a version of FFT that works with this field.

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Riccardo has figured out we can interpolate the 5 evaluation points we need directly without constructing coefficients using Barycentric interpolation, total cost O(N * 5) rather than O(N^2) for general lagrange or O(N log N) for FFT

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Issue still open - @odraccir1 reports that we still need mixed-radix polynomial multiplication

"This goes along with the merged geometric interpolation and will be used in the decryption, since the full coefficient polynomials for A, B, C are required to calculate H."