Start refactoring to geary setter pattern

[0ffz]

• Convert different parts of furniture init process into setter actions. These are geary listeners that get called on entity spawn/reload, currently these are:
  • Setting item based on set.item, including colorable items
  • Setting MEG model
  • Setting seat height
    • Add clearFurnitureSeats method to support hotswapping, also don't persist these entities, this is a step to fully packet based seats in the future.
• Spawn furniture via geary's AttemptSpawn system, this lets us spawn directly from prefab at a location.