WIP Add support for Ed25519, Ed448, X25519 and X448. RFC 8037

[atombrella]

This is still pretty much WIP!

• [ ] https://github.com/google/wycheproof Has vectors that may be interesting for edge cases.
• [ ] Add tests for all key types.
• [ ] Revert typo fixes for non-relevant code parts (could be moved to a separate PR)
• [ ] Fix Mypy issues for JWKOkt
• [ ] Reconsider if OpenSSL vendors all of the algorithms, or just a subset of them.

[atombrella]

Please see issue #45

[atombrella]

@JamesTheAwesomeDude You're welcome to assist a bit in getting this in a mergeable state.