Bathroom Corner Shelf Splitable

Made some small changes to the original so that I could easily break up the print for my smaller printer with my slicer.

Changes:
- `TraySplitline.stl`: has some of the hexagons filled in so it can be sliced in half with peg connections or similar
- `RailsSplitline.stl`: middle rail is wider so connections can be inserted easily

otherwise the files are the same.