Support having unlisted pages

[mthaddon]

After some recent discussions with the Documentation team I was asked to remove the link to the "Roadmap" page (https://charmhub.io/nginx-ingress-integrator/docs/roadmap) from the navigation. It's linked in the README directly, and was felt to be unnecessary to list separately in the navigation.

To do so I had to add the following the end of the discourse navigation table in the /docs/ index:

|  | roadmap | [Roadmap](/t/nginx-ingress-integrator-docs-roadmap/7432) |

Apparently it breaks if it's not the last element (hopefully if you need multiple hidden elements that possible too...

Is it possible for this project to support that somehow?

[jdkandersson]

Yes it should be possible, I can see how this works. I assume that if the level field is not filled in, it doesn't show up but can be linked to.

Discuss this in combination with #26, the proposed solution there will support this as well