feat: add Grumpkin elliptic curve (native 2-cycle with BN254)

[yelhousni]

Description

This PR implements arithmetic over the Grumpkin elliptic curve as native operations in a BN254 SNARK. This is similar to sw_bls12377 and sw_bls24315 packages, except there is no (efficient) pairing on Grumpkin. This needs Consensys/gnark-crypto#625 to be merged first.

Grumpkin forms a 2-cycle with BN254 and the combination is useful for many protocols.

TODO:

• implement endomorphism-based optimizations.

Type of change

• New feature (non-breaking change which adds functionality)

How has this been tested?

Arithmetic tests against gnark-crypto are implemented + edge cases.

How has this been benchmarked?

	r1cs	scs
scalar mul	1,724	4,899
joint scalar mul	3,100	8,500

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I did not modify files generated from templates
• golangci-lint does not output errors locally
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules