[proposal] Add AES and NIST curve support to the DIDComm implementation

[mirceanis]

We're currently using only X25519 keys with ECDH-ES or ECDH-1PU + XC20P for key agreement and wrapping, and XC20P for content encryption, but XC20P is only listed as optional:
https://identity.foundation/didcomm-messaging/spec/#curves-and-content-encryption-algorithms

We need AES support for content encryption and key wrapping and P256 & P384 key support too. to be fully spec compliant in terms of algorithms.

It's likely that these features will have to be implemented in the lower level did-jwt library which is being used for JWE.
I believe that @stablelib (the lib that is used for encryption support) should already have all the primitives needed.