Add Google Protobuf hive protocol types definitions

@hb @wkedzierski @marek @kmochocki

This preliminary step just to present a technology leap in interactions between Hive core and popular stacks like TypeScript/JS or Python. The goal is to provide common definition of blockchain critical definitions (operations, transaction), which transformed to language targeted stubs will provide well OOP capabilities for building new transactions like also processing those already accepted by blockchain.