perf, feat, refactor: improve some plonk primitives

[gbotrel]

Description

New feature

• adds kzg.ToLagrangeG1(..) by @ThomasPiellard

// ToLagrangeG1 in place transform of coeffs canonical form into Lagrange form.
// From the formula Lᵢ(τ) = 1/n∑_{j<n}(τ/ωⁱ)ʲ we
// see that Lᵢ = FFT_inv(∑_{j<n}τʲXʲ), so it suffices to apply the inverse
// fft on the vector consisting of the original SRS.
// Size of coeffs must be a power of 2.
func ToLagrangeG1(coeffs []curve.G1Affine) ([]curve.G1Affine, error) {

Refactor

• fft.Generator() moved to fr.Generator() (keeping previous one for compat)
• iop.Evaluate takes an additional parameter that optionally provide a buffer for the resulting slice
• polynomial conversion operations takes an optional NbTask parameter forwarded to the fft to leave the caller chose degree of paralellism
• ***/fr/kzg moved to ***/kzg by @ThomasPiellard

[github-actions]

Summary

✅ Passed: 5943
❌ Failed: 0
🚧 Skipped: 5

🚧 Skipped

• TestReference (github.com/consensys/gnark-crypto/ecc/bn254/fr/sis)
• TestAppend (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)
• TestLimbDecomposition (github.com/consensys/gnark-crypto/ecc/bn254/fr/sis)
• TestAppendSis (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)
• TestCommitmentSis (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)

[github-actions]

Summary

✅ Passed: 5943
❌ Failed: 0
🚧 Skipped: 5

🚧 Skipped

• TestAppend (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)
• TestAppendSis (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)
• TestCommitmentSis (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)
• TestReference (github.com/consensys/gnark-crypto/ecc/bn254/fr/sis)
• TestLimbDecomposition (github.com/consensys/gnark-crypto/ecc/bn254/fr/sis)

[github-actions]

Summary

✅ Passed: 5943
❌ Failed: 0
🚧 Skipped: 5

🚧 Skipped

• TestReference (github.com/consensys/gnark-crypto/ecc/bn254/fr/sis)
• TestLimbDecomposition (github.com/consensys/gnark-crypto/ecc/bn254/fr/sis)
• TestAppend (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)
• TestAppendSis (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)
• TestCommitmentSis (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)

[github-actions]

Summary

✅ Passed: 5943
❌ Failed: 0
🚧 Skipped: 5

🚧 Skipped

• TestReference (github.com/consensys/gnark-crypto/ecc/bn254/fr/sis)
• TestLimbDecomposition (github.com/consensys/gnark-crypto/ecc/bn254/fr/sis)
• TestAppend (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)
• TestAppendSis (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)
• TestCommitmentSis (github.com/consensys/gnark-crypto/ecc/bn254/fr/tensor-commitment)