Prusa MK3s Extruder Carriage for Bear X-axis

This is a modification of the original R4 extruder carriage for Prusa MK3s / MK2.5s to make it compatible with pekcitron's Bear X-axis, as the MK3s STILL does not offer a decent X-axis belt tensioning mechanism.

The original Prusa carriage was modified in Solidworks based on the sources by jzkmath.
The belt path is modified to match that of the Bear Extruder but is otherwise completely compatible with the MK3s extruder.

The belt chanel was tightened w.r.t. the original prusa model to pre