JSON-LD Sign/Verify endpoints do things differently than ICv2/PPv2

[dbluhm]

The JSON-LD Sign and Verify endpoints provide a mechanism for doing LDP signatures on JSON-LD documents and verifying signed JSON-LD documents. Issue Credential v2 and Present Proof v2 provide the DIDcomm interface for doing the same when using the ld-proof-detail attachment format. The scope of these components is of course different; however, at some point in the call stack, they should probably be calling the same code for signing and verifying signatures. They do not.

This has the additional side effect that recent updates to add additional Signature Suite types to the JSON-LD signatures are not usable from the sign/verify endpoints.

These endpoints should be updated to use the same underlying calls as ICv2 and PPv2.