Verifies a zcap capability against one generation of the realm's key and
checks it against the presentation context; the caller tries each live
generation in turn.
Parameters
value: unknown
the presented token value
keys: any
{ cryptosuite, controller, keyId } plus publicKey or
publicJwk
Verifies a zcap capability against one generation of the realm's key and checks it against the presentation context; the caller tries each live generation in turn.