Making Sdf2DWorld work with networking

[trundlr]

Another PR for you to look at if you are interested 👀

• An SdfWorld and all its chunks exist on a single GameObject
• Chunks are not being created per modification, but work as intended and are networked. Modifications are not their own GameObjects, as 1) gameobject iteration is a major pain point in scene right now for performance and 2) it would be overkill for something like Grubs anyway
• Codegen for Broadcast functions seems to be failing for classes with a bunch of generics in the header (didn't really test this extensively) so I created a separate component instead
• SdfChunk uses SceneObject + PhysicsShape instead of components. IMO this is cleaner and more closely mimics the old behaviour anyway. I found I was having a hard time offsetting the chunks with ModelRenderer, as it is written to follow the transform of the parent GameObject. Pol works around this by manually offsetting the vertices.

https://github.com/Facepunch/sbox-sdf/assets/57276947/508475b7-722e-48df-b86a-8575391c9ebb

[Metapyziks]

Thanks for this, I'll revisit when we can properly include libraries again: Facepunch/sbox-issues#5053