This commit adds proto rpc definitions for the communication needed for
the CLI interface.
This will allow us to move the rest of the CLI interface over to gRPC
and in the future allow remote access
This commit changes the way CLI and grpc-gateway communicates with the
gRPC backend to socket, instead of localhost. Unauthenticated access now
goes on the socket, while the network interface will require API key (in
the future).
