feat: introduce MaterialHandle and zCMaterialManager

[kirides]

• MaterialHandle represents a generationally tracked index into a flat zCMaterial* vector.
• zCMaterialManager holds and validates any Handles.
• Engine uses MaterialHandle for geometry and vobs which live for a long time. Things like PolyStrips are knowingly excluded as they are short lived and their material will likely always be valid.
• MeshKey uses MaterialHandle to ensure any left-over and overriden zCMaterial* with the same pointer but different value are ignored.
• Workaround for G2 where the engine constantly creates new zCCamera and with that new zCMesh and zCMaterial just to grab the "default" NearPlane value of a freshly constructed camera.
  instead we just grab the fresh NearPlane of any zCCamera that gets created and store that and provide it to the engine.

[kirides]

@Krystian12421 do you want to take a look at this? After your cleanup of the resources.

This PR allows actually tracking the lifetime and count of zCMaterial* instances and ensures out-of-date handles never reach the rendering part

[Krystian12421]

@Krystian12421 do you want to take a look at this? After your cleanup of the resources.

This PR allows actually tracking the lifetime and count of zCMaterial* instances and ensures out-of-date handles never reach the rendering part

I can test it tomorrow