X-Carriage-Cover for original Prusa MK2.5

This is a remix of the very nice X axis carriage cover by jltx. It's based upon the MK2.5 Prusa part with the same openings added as on the jitx part. It allows much easier access to the X belt for changes and adjustments. With the original Prusa part, substantial disassembly is needed if the belt needs to be replaced or for coarse adjustments.

The modification to the jitx piece is very minor and moves the hole for the wire support to the side. It's in a different position on the MK2.5 than o