implement node builder so the user can specify the material node that he wants created on importing zbrush data

[kromar]

the plan behind this node builder is to have a modular node system rather than a hardcoded node tree where the user can define a node templates to his own needs so the data coming in uses those custom nodes. This should make the whole material import a lot more flexiable and reduce maintenance compared to a hardcoded system.

material wrapper https://wiki.blender.org/wiki/Reference/Release_Notes/2.80/Python_API/Modules

https://github.com/blender/blender-addons/blob/084eec36977c9a084aa020031f4a1aa0f0352170/io_scene_obj/export_obj.py#L70