Molang Variable Changes

With the change to the render pipeline in 5.0, Molang Variables had to change. Previously, queries could be defined and updated at any time during the render process. This was a problem with a new instance-based rendering pipeline because there's no animatable instance at render time.

To combat this, Molang Variables, and by extension all MathValues, have been converted from a DoubleSupplier to a ToDoubleFunction, taking in the ControllerState from the current render pass. This allows for queries to be dynamic whilst still supporting an instance-based render pipeline.