Demo: net-code/rollback/finite state machine with 2 physics systems

[PhoenixIllusion]

Dependent on save/load state API

Demo:
Two scenes with 2 plugins

Ensure both load same system

Ensure both have a rolling ring-buffer of save states

Assume one Body per player

Have a recording of player 1 and player 2 actions for given time window

Start demo

Each scene will play its own recording
Each scene will send its own instructions to the other scene with a random time offset in the past, greater than zero but less than the ring-buffer size

At the end of the demo, once the last instruction is received by both scenes, confirm both demos are both matching a fixed pre-determined outcome and each others own internal state