Add Wallet Attestation Profile

[tlodderstedt]

trafficstars

define how wallet attestation is implemented based on client attestation draft

[tlodderstedt]

I think we also need to add claims to the proof issuance request parameter to indicate key type and user authentication method used to protect access to the key, so the issuer could refuse to process if its requirements are not met. I guess this also requires respective metadata to let the wallet know in advance what is required.

[tlodderstedt]

PR #52

[Sakurann]

PR was merged