Customizable front panel button for Anycubic Kossel

A customizable button for the front panel LCD (a RepRapDiscount 2004) on the Anycubic Kossel line of printers (including the Anycubic Kossel Plus / Anycubic Kossel Linear Plus). Based on @HaTomX's Kill Button for Anycubic Kossel, but redone in OpenSCAD and with a few tweaks.

Since the STL previews don't show the text without using Thingiview and looking at the bottom of the print, I have provided the following options:
- PANIC!
- STOP!
- [Exclamation triangle](https://fontawesome.com/icons/exclamation-triangle)
- $#!%
- *A back arrow*
- [back chevron](https://fontawesome.com/icons/chevron-circle-left?style=solid)

I use [Klipper](https://www.klipper3d.org/Features.html) for my Kossel Plus, so it is easy to reconfigure the purpose of the button on the LCD panel. I trust the power switch more for an emergency stop than a pin which needs to be sampled by software, and it is also on the front of the printer. Therefore I decided to repurpose this button as a quick "back" butto