Add support for a spring and a joint on the same axis for godot impl.

[appsinacup/godot-rapier-physics#459](https://github.com/appsinacup/godot-rapier-physics/issues/459) Godot exposes a Generic6DOFJoint3D which has both a motor and a spring on each of the 6 DOFs which, does not seem to be possible with the current 1 motor per DOF which is also used for a spring model. Expected behaviour (simulated with Jolt3D): https://github.com/user-attachments/assets/99226088-4740-499c-8666-375c0f75f874