Ploopy Trackpad clickpad conversion

This is a mechanism to turn the [Ploopy trackpad](https://ploopy.co/trackpad/) into a clickpad. The design is heavily inspired by the Apple iPad Pro keyboard's trackpad mechanism and can be clicked anywhere on its surface, unlike many laptop clickpads.

Even though it was not designed for a switch, I used the the GPIO for the unstuffed diagnostic LED, GPIO24.

There are two variations- one with the trackpad flat and another with it angled. Both models use the original trackpads top surface, bootloader cover, and `omniclick hinge.stl`. The only difference is the flat version uses `omniclick flat support.stl` and the angled one uses `omniclick angled support.stl`.

###Part Printing
Because it has living hinges (hinges made from the plastic itself), the hinge part should be printed with a relatively flexible filament like PETG. The material for the supports doesn't matter so much, and may benefit from a stiffer one, though I used PETG throughout.

The hinge and flat support can be printed