Customizable wall mounting bracket for rectangular device with power cord / screen slot (Heltec v3 Meshtastic node example)

This is a customizable wall mounting bracket for any "rectangular" device that has a power cord coming out the bottom and/or a screen on the front panel. You pick the internal dimensions of the "hole" (make it 1-2 mm larger than the object you want to wall mount for easy "slip in/out") as well as the width and depth of a slot that is cut into the bracket. The slot is useful if your device has a power cable coming out of the bottom and/or a screen/buttons you want to be able to see/access without removing it from the bracket.

WARNING: Thingiverse Customizer appears to be using an outdated version of OpenSCAD and it won't work with it. (This is annoying after I spent an hour moving all the dependancy code into the main file....anyways, I've left it here in case Thingiverse upgrades their OpenSCAD version of customizer, it should magically start working. Otherwise, download it and use OpenScad version 2021.01 or later.

The bracket is currently set up for 2x number 8 wood screws, but