Refactor client-server network communication

[Alanine42]

Problem:

Every time we add a new game field, we have to update across ClientGame, ClientNetwork, NetworkData, ServerNetwork, ServerGame...

Pain.

Fix:

An easy fix would be to reuse the ServerToClientPacket struct (or give it a better name, plz) that holds all sync-able game data and use it across ClientGame, ServerGame, and network.

[Alanine42]

welp, no longer needed