Refactored Node3D rotation modes

* Made the Basis euler orders indexed via enum.
* Node3D has a new rotation_order property to choose Euler rotation order.
* Node3D has also a rotation_mode property to choose between Euler, Quaternion and Basis

Exposing these modes as well as the order makes Godot a lot friendlier for animators, which can choose the best way to interpolate rotations.
The new *Basis* mode makes the (exposed) transform property obsolete, so it was removed (can still be accessed by code of course).

scene/3d/path_3d.cpp

@@ -248,6 +248,7 @@ void PathFollow3D::_validate_property(PropertyInfo &property) const {
 
 		property.hint_string = "0," + rtos(max) + ",0.01,or_lesser,or_greater";
 	}
+	Node3D::_validate_property(property);
 }
 
 TypedArray<String> PathFollow3D::get_configuration_warnings() const {