Adjustable front facing Z limit switch mod for Tevo Tarantula

This simple mod makes it easier to adjust the heights of the Z limit switch when the printer is accessible just fron the front side (e.g. when it is stored in an enclosure). there are two parts to be printed, one needs to be mounted directly on the X axis using the already available screws and the other is to be fixed on the external frame using additional screws and T-nuts. If the extruder is mounted on the same side of the frame (as in the picture), take care that the screw holder do not hit i