Maybe change crypto/secp256k1 dependency library

Nobody has claimed this yet.

We are currently using `github.com/decred/dcrd/dcrec/secp256k1/v4` for our secp256k1 cryptography. It seems Lotus folks have recently switched to `gitlab.com/yawning/secp256k1-voi` for their secp256k1 crypto for reasons I don't yet understand. Some Lotus folks have asked if we should move to that library as well.

I'm opening this issue to try to understand and document if there's any benefit to moving to the yawning crypto, or some other crypto library (https://github.com/mit-plv/fiat-crypto was also brought up).

Note: I don't think there is a compatibility/interoperability issue here, as any correct library should work interoperate.

Could folks with more context please chime in on one would prefer `gitlab.com/yawning/secp256k1-voi` or `fiat-crypto` or specifically not our current `decred/dcrd` library. And, relatedly, why go-libp2p in particular would benefit?

cc
@AnomalRoil – Expressed preference for the yawning library
@Stebalien – Involved in the change for Lotus
@ribasushi

Start by comparing the current github.com/decred/dcrd/dcrec/secp256k1/v4 dependency with gitlab.com/yawning/secp256k1-voi and fiat-crypto. Review the linked Lotus context and determine whether go-libp2p has a concrete benefit from changing libraries. Done means documenting the comparison, compatibility considerations, and a reasoned recommendation.

Written by the indexing model from the issue text.