Adjustable Z endstop with cable guide (Q54153)

This is a derivation of kwixson Adjustable Z endstop. I've added a small protrusion with a 4mm hole which is designed to provide a tie point for the electrical wiring for the x-axis motor and associated endstop. The tie point isolates movement of the electrical wiring away from where it connects to the motor and endstop. This protects the electrical wiring at the key points where it joins the motor and endstop. I had a further need of this isolation than a standard Prusa might, as I have added electrical quick disconnect points for each of my motors and endstops (in order to make maintenance simpler).