Use new algorithm IDs for CFRG curves instead of OIDs

This is an alternative to !240 (closed) (and !223 (closed)).

It defines new algorithm IDs for X25519, X448, Ed25519, and Ed448.

X25519 is used with HKDF-SHA256 and AES128-KW.
X448 is used with HKDF-SHA512 and AES256-KW.

It marks the Curve25519 and Ed25519 OIDs and EdDSA algorithm as legacy, and removes the X448 and Ed448 OIDs.

The example keys still need to be updated, I will do so if folks are in favor of this change :)