consider adding MTI crypto suites

[Sakurann]

There has been feedback from EUDIW that having a small list of MTI (mandatory to implement) crypto suites for multiple things would greatly help for interoperability. Below is probably a least controversial list..?

Issuer Signatures:

• ECDSA using secp256r1 and SHA-256

Key binding/presentation and Verifier Signatures:

• ECDSA using secp256r1 and SHA-256

Encryption (if needed):

• AES-256-GCM

Hashing:

• SHA-256