RFC: Consider Ed25519

[damip]

Consider switching from secp256k1 ECDSA to Ed25519 EdDSA because:

• has better security features than secp256k1: http://safecurves.cr.yp.to/
• most commonly used scheme in Tezos, default on Solana and m any others
• Faster than secp256k1 https://justmoon.github.io/curvebench/benchmark.html
• safer and more standardized Schnorr / multisig implementations

Some info: https://soatok.blog/2022/05/19/guidance-for-choosing-an-elliptic-curve-signature-algorithm-in-2022/

[damip]

Validated by @qdrn and @sebastien-forestier