Add EdDSA support for WebAuthn signatures

[conr2d]

Currently, Noir only supports ES256 for WebAuthn signatures, as it is one of the default algorithms (ES256, RS256) commonly supported by browsers. To utilize the secp256r1 curve, Noir has introduced a dependency on p256.

It has been confirmed that the Chrome browser supports EdDSA. If the ed25519 curve can be used for WebAuthn signatures, it could reduce additional dependencies and enhance compatibility with existing account IDs. It is necessary to verify if other browsers have also added support for EdDSA and whether the implementation is compatible with what Substrate supports.

[conr2d]

We cannot add custom host functions to Polkadot parachains, so adapt webauthn module to support ed25519.