Support key resolution of JWK-based DID VerificationMethods (publicKeyJwk)

[gmulhearn]

Currently we do not support the ability to translate a VerificationMethod with a JWK-based key (publicKeyJwk field) into public key bytes (and transitively into a public_key::Key). This is a bottleneck in allowing us to use JWK DIDDoc verificationmethods for crypto (e.g. checking a signature from a JWK VM)

area to be improved:
https://github.com/hyperledger/aries-vcx/blob/main/did_core/did_doc/src/schema/verification_method/public_key.rs#L46