Bambu Filametrix Printhead for Voron Stealthburner

This is a remix of Ibot_3D's excellent Voron Stealthburner printhead for the Bambu hotend.  Changes include adding support for Filametrix, moving the wire path out of the way of the filament cutter, and tightening the slot for the hotend's heatsink to eliminate a minor gap and potential for wobble.  Some of the geometry was slightly modified to remove mesh artifacts.

Modified parts to use Filametrix filament cutter.