Added the JSON-LD context for DIDComm v2 and the accept item to the DIDComm v2 service entry
Added the JSON-LD context for DIDComm v2 and the accept item to the DIDComm v2 service entry

Signed-off-by: Stephen Curran <941e58e189f3c1f0cc08828d7f189c0a4fce1702@gmail.com>

sovrin-foundation/sovrin,sovrin-foundation/sovrin,sovrin-foundation/sovrin