Split the demo page

[flo-dup]

Describe the current behavior

The demo page is growing with more and more diagrams

Describe the expected behavior

Split the demo page in 3 at least (map / nad / sld) to have a reasonable number of diagrams in the page displayed

Describe the motivation

Easily test the features

Extra Information

No response

[flo-dup]

#326 started the work by adding a new page and a toc, hence the splitting should be straightforward after that PR.