Add CLI tools usage examples and references to documentation

[RandyTheOtter]

I can't read documentation contribution guides because links in CONTRIBUTING.md and README.md are currently broken lolol

p.s. Idea comes from here

[RandyTheOtter]

Seems okay to me.

Nested list rendering is a bit ugly. Still readable and also this problem should really be fixed in the renderer.

Another concern I have is that I don't actually tell how to install documentation (the man kind). Advanced users of cli really should know this by themself.

[rapenne-s]

Thanks! I merged it in both main and r4.2 branches.