Add fields for custom bone names for BVH import [Feature Request]

[Makkarob]

When recording .BVH, all bones are named the same as in SlimeVR Server. Some programs recognize bones by name, and to work with them you have to manually rename all the bones in each .BVH file before importing. It would be nice to have a separate field for each bone (not the tracker, but the bones of the skeleton) where you could enter the name before recorde.

[ZRock35]

I support this, perhaps including a way to deselect certain bones from recording (if armature doesn't support it)

[electromuis]

Shouldn't be too hard. Let me take a crack at it