A bunch of errors still

- Added support for seat enter and exit events and a test for them
- Added support for entering and exiting seat from code
- Changed the Id property of ECS objects to non-abstract, requiring it in the constructor, so that the Player class can inherit EcsObjectBase
- Added a weird constructor to EcsObjectBase that allows running code to determine the object Id
- Added interface for engines that receive entity functions
- Exposed the entity submission scheduler and removed it from FullGameFields because it moved from there
- Made the Game.Enter event only fire after the first entity submission so the game is fully initialized and the local player exists
- Added all seat groups to the dictionary