Code on the landing page

Our landing page currently mostly has text and figures (and a video), but does not show any code. I also think that with a code example, everything becomes clearer.

A nice example of this approach is pyiron: https://pyiron.org/

We could insert some (pseudo)code, demonstrating the main idea and potentially some features (e.g., that the API calls are the same independent of the coupling algorithm). We could even use tabs to showcase different languages (see #211), or even additionally link to an interactive platform such as mybinder or codeocean.

I would like to work on this (but it's low priority).