Add ignore_nurbs argument to fbx importer

When importing an fbx containing NURBS data, an empty is created for each NURBS surface in each NURBS shell, the latter also referred to as leafnode in some contexts. In a big model with many fillets, this results to thousands of empties in Blender which carry no data other than the name of the surface, ie no geometrical data. Until such time when NURBS geometry is created from the NURBS nodes in the fbx, an argument to the import_fbx function to ignore them would be very useful.

In: projects.blender.org/blender/blender/src/commit/22930ee04c5ef754102dff1052c5d947a80c9cb9/scripts/addons_core/io_scene_fbx/import_fbx.py

There are references to the fbx documentation:

help.autodesk.com/view/FBX/2020/ENU/

which mentions some relevant node attributes within the fbx format:

FbxMesh, FbxCamera, FbxLight

which are populated in blender during import. It also mentions:

FbxNurbs, FbxNurbsCurve, FbxNurbsSurface, FbxTrimNurbsSurface

These are not dealt with in the fbx importer as of Blender 4.2.1 LTS yet still cause empties to be created. If an additional argument was added to the import_fbx such as "ignore_nurbs=True" then any node with any of the attributes listed above could be ignored, greatly speeding up the import process in cases where the fbx file contains NURBS data. There are already similar arguments such as "ignore_leaf_bones". While at it, ignore_lights, ignore_cameras and ignore_mesh could be added as well I suppose but they do not share the issue currently where they are only partially imported like the NURBS data is.

Our current workaround involves removing all the childless empties created from the NURBS nodes from the fbx post import, but the import is greatly slowed down by needlessly creating thousands of empties, one for each NURBS surface, and then spending additional time searching the import for childless empties to purge them.