Stop using pkcs8 for generating Ed25519 key pairs

[joepio]

I'm working on a JS implementation of Atomic, which means I have to use some library that supports the same crytpo stuff for signing and validating commits. I've picked Ed25519 for it's high security, resistance to timing attacks and performance, but it's kind of new and support isn't awesome at the time. However, I've found a nice JS library (noble), but that doesn't support pkcs8 deserialization..

So I guess the best way forward is to break all existing keys and switch to non-pkcs8 serialization of seeds 🤷 .

Issue in atomic-react: atomicdata-dev/atomic-data-browser#3