Update protocols to use new protobuf encoding

[aloknerurkar]

Currently, we have 2 protocols already. By the time this issue is started we might have another one. They are using msgpack encoding right now to exchange messages. Instead they should use protobuf implementation.

Tasks:

1. Define the protobuf messages. These would be similar to the existing structs used.
2. Generate pb files for the proto specs.
3. Update the protocols to use the new types and use the protobuf encoder/decoder to read/write.
4. Update any tests required in the protocols.