[DOCS] enable nice Toggles

[hmd101]

We want to hide some complexities on our Documentation sites in Toggles. However the current rendering of Toggles looks awful, e.g., see here.

I suspect we just have to find the right mkdocs features and include them. For that, this may be a helpful start: https://smarie.github.io/mkdocs-gallery/

Useful resources:

• Python Markdown Extensions
• mkdocs-toggle-sidebar-plugin (not exactly what we're looking for but maybe of interest)
• Other useful plugins

Should be something along these lines:

markdown_extensions:
  - pymdownx.details
  - pymdownx.superfences # Optional: allows toggles inside code blocks