Tracking Issue: Migrate transport level logic into backroll-transport

[james7132]

There are a notable amount of the application level protocol that belongs in a lower level implementation. The heartbeat, the initial synchronization, the magic number management, sequence number, and disconnect timeout are all to establish a unreliable but ordered connection, something Laminar and other reliable UDP implementations already support. This should exist at the backroll-transport layer. A good amount of this is already established in TimonPost/laminar#290, and this change be considered a step towards implementing backroll-transport's connection model in Laminar.

• Create a wrapper around Peer for ordered unreliable sends. OrderedPeer?
• Add a way to notify the main game of incoming connections.
• Alter Peer to notify either end of a network interruption.
• Move "Synchronizing, Running, Interrupted, Disconnected" state machine to the transport layer.
• Move heartbeat task into OrderedPeer