Allows stacking 3.5in HDD using bottom and side screw holes.

Uses standard #6-32 UNC PC screws (four at the bottom of the top drive and up to six on the sides of the bottom one.

Inspired by version made for 2.5in drives:
[https://www.printables.com/model/269975-ssd-stackers-25-hdds-work-too](https://www.printables.com/model/269975-ssd-stackers-25-hdds-work-too)