listner changes for grpc

GRPC changes coresls with latest updates 

1. Fix: 412 jwt precondition failed. The open request was setting empty token in response causing 412 for further restricted requests.

1. Add: Process post hook for nil data

1. Fix: Panic if selected single object is not included in final result. The post hook was dereferrencing nill data resulting in panic.

1. Fix: Rolebased services can be accessed by restricted user

1. Add: Service caller, calls a service by name from bl

This reverts commit 5571f2a3