More Nim on more Microcontrollers!? (Arm CMSIS / Zephyr RTOS)

[shirleyquirk]

Pio is assembly plus some hooks to the main language. If you look 
[here](https://github.com/raspberrypi/pico-sdk/tree/master/tools/pioasm) in the 
repo for `pioasm` you can see there is code generation code for c, Ada, and 
python, so Nim support could be added there, perhaps