Support for RFC-to-be 9864 fully-specified ECDSA/EdDSA

[BrianSipos]

The document deprecating existing ECDSA and EdDSA and allocating new code points for fully specified versions of those algorithms (mandating specific key curves) is in the RFC editor's queue and about to be published.

The specific new code points are defined in Section 4.2.1 and have identical behavior to the deprecated code points other than requiring a specific key curve for each algorithm.

[BrianSipos]

I can help with a PR to add the new algorithm code points, besides the name and value the 'normal' behavior is the same as current algorithms.

I don't know about a mechanism to restrict specific key curves though, because I don't think anything like that exists currently. A new member can be added to the algorithm and the sign/verify functions could check for that member and compare curves.