Extending classical Arduino toolchain with LDC2/AVR

[Dmitry Ponyatov]

> adr has examples for this somewhere. Check this 
> https://dpldocs.info/this-week-in-d/Blog.Posted_2022_10_10.html

Thanks, I also found a first step variant with empty `.ino` file 
and cross-generation into `src/dlanged.S` assembly with LDC2.

Next step is more complicated: manual writing binding with 
Arduino core and side libraries.