Add support for EdDSA

[kbolino]

Please add support for the EdDSA signature algorithm. Its use with JWT is specified by RFC 8037 and it would be useful for cases where one already has e.g. an Ed25519 key on hand.

[artooro]

Does this project still have an active maintainer? Nothing has been merged yet in 2024 I wonder if someone were to contribute EdDSA support if it would even get accepted.

[dannys42]

Yes, I can merge if someone is able to contribute and create appropriate unit tests.