Parametric BLTouch rear sensor mount

This is a remix of https://www.thingiverse.com/thing:2219963 to allow mounting a BLTouch sensor on the rear bearing of an Anet A8. I've included the customizer to allow the height
and many other features to be custom set for any printer . The "Measured Height" parameter is used to calculate the correct height with the 8.3mm offset to the nozzle. You simply need to move the print nozzle so that it touches the bed then measure the distance of top mount screw hole (on the rear lower bearing) to the bed. Enter this in the "measured height" field and create. The mount also includes side clearance to allow it to work on new Anet A8's. Please note that for this mount, you need a mount to bed distance of at least 44.8mm (sensor height + 8.3) or it won't work.

Uses 4 3x10mm bolts for both the sensor and backplate mounting

Stock carriage settings:
define X_PROBE_OFFSET_FROM_EXTRUDER 10
define Y_PROBE_OFFSET_FROM_EXTRUDER 53

define FRONT_PROBE_BED_POSITION 53