Implementing cta-admin functions in cta-frontend-grpc

Problem to solve

Implementing cta-admin functions in cta-frontend-grpc. Most commands (that have a simple Request/Response format) should have already been covered by the Request/Response class mentioned in #38. Some additional work is needed to implement gRPC streaming for the ls commands or any command that has an arbitrarily-long response. Additionally the front end should support kerberos authentication.

Stakeholders

dCache team