[FEATURE REQUEST] Export model with fake bones if skeleton is not found

[Tosyk]

Hi, I thank you for your work on the modified version of AS!

I came across with the need of an option to export model with fake bones if skeleton is not found. Fake bones will force AS to wright weights in the FBX. WE ONLY CARE ABOUT WEIGHTING DATA. Fake bones might not have hierarchy and can be in the origin of the model.

Later on, we could take this model file + file with skeleton and merge them in blender.

This is a general improvement of AS. Not really related to any game specific modification of AS.