Viss client grpc

[nayakned]

This PR can be tested once the #287 is merged.

How to use the kuksa VISS Client for gRPC.

• Ensure that the kuksa.val server implements the get/set/authorize gRPC calls (done in PR New implementation of the gRPC set, get and authorize. #287 ).
• Start the client. It will automatically connect using ws protocol.
• Disconnect it using disconnect command
• Change Server Address using setServerAddress command and use -p switch to change the protocol
  -- If insecure mode, IP address would suffice, e.g., setServerAddress -p grpc 127.0.0.1 50051
  -- If secure mode, server name (be default: Server ) is needed from the used certificate, e.g., setServerAddress -p grpc Server 50051
• Connect using connect command
  -- insecure mode: connect -i
  -- secure mode: connect
• Finally execute commands as usual.

[SebastianSchildt]

Working now. Not worse than before :)