[Grbl_Esp32 Issue#163] Suggestion: Adding Atmel 32u coprocessor

Hello!
I’ve been thinking about this for a while and would love to hear different opinions. So to start off, I have designed a board that uses a ESP32 module instead of a dev-board with a CP2120 USB-Serial chip and 3 TMC2208 drivers.

So I had the idea to swap the CP2120 with an Atmega 32u and use HoodLoader2 to have usb to serial plus a bunch of extra pins that could be used for expansion, similar to the suggestions brought up in #50. This way I could also use UART to configure the TMC2208 ICs.

That said, this is my first more complex hardware project and a great learning experience. Thus before going ahead and designing a board like this i thought I’d post this here and hear a few other opinions.