Support Ed25519ph

[zamicol]

Paul currently supports Ed25519. We're hoping Paul will implement Ed25519ph soon: paulmillr/noble-ed25519#63

The W3C Web Cryptography API recommendation also omits Ed25519, so an external package that implements the Ed25519 primitive is used. The upcoming update FIPS 186-5 specifies Ed25519 support. (https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-5-draft.pdf, section 7.8) Hopefully this will motivate Javascript to include Ed25519.

See also:

• Support Ed25519 and Ed25519ph CozeJS#2
• https://cyphr.me/ed25519_tool/ed.html
• https://github.com/Cyphrme/ed25519_tool