Open Trackpad Controller

Game controller with trackpads
Inspired by Steam Controller

Hardware:
* WeAct Studio Black Pill stm32f411ce
* elan 33200v-3600
* Bunch of 3d prints

Requires ps2elantech library
https://github.com/NepEgor/ps2elantech

Credits:
* hid_def: https://github.com/katyo/hid_def
* xinput descriptors: https://github.com/zlittell/MSF-XINPUT