Add furniture to game

[snipercup]

This requires #34 to work. I will publish this PR as a draft to make sure #34 gets merged first.

This pr adds furniture to the game

• Loads sprites from the furniture definition
• Can be moved by the player, even up and down slopes
• Can be moved by mobs too
• Can be shot and destroyed
• Is saved and loaded when you restart the game
• This pr is only for physics enabled furniture like tables and chairs. There should be a separate PR for static furniture like trees and fences.

There are some problems with the furniture:

• They are lit when behind a wall even though you should not be able to see them (at least not that brightly)
• Weight and friction does not affect movement so a chair and a filled bookcase are equally easy to move
• Furniture jumps around when pushed against the wall
• Collision shapes are all the same. It's a sphere so you are really pushing a ball around when you push furniture
• The furniture has dampening 59 which prevents them from floating away. The downside is that they may fall very slowly, haven't tested this much

I experimented with the physics for a bit. We can change the sphere collision shape to a box and then lock the x and y rotation so it can only rotate on the y axis. The problem with this is that it introduces weird behaviour where you can push furniture in one direction but not the other even though there is nothing blocking it. Pushing up slopes is very difficult with only a little weight applied. The benefit is that we can introduce weight and friction and it won't clip into the wall as much as the current implementation. My guess is that if we want this there will be some custom code and it will take time to get rid of all the bugs

An alternative is that we switch to Jolt physics, something that has been advised when I looked up help on the rigidbody3d. It shouldn't be too hard to implement and it works with Godot 4.2. Jolt physics is not entirely bug free either but it has been recommended as an alternative to Godot native physics.