docs: showcase beautiful examples of generated trees

[castarco]

It would be nice to have a small collection of examples of beautiful trees generated with our library.

[AvaterClasher]

Can i be assigned this ?

[castarco]

Hi @AvaterClasher , yes, of course! It's yours.

Maybe we could place it (for now) in a file called examples.md inside the docs/ directory. We still have to think how to organise the documentation once it starts to grow, but we can advance on the examples anyway.