Updating project roadmap

[laeti-tia]

Our public roadmap at https://www.perfsonar.net/project-information/project-roadmap/ is out of date (show 4.1 plans). We should update it to 4.3 and 4.4 plans and update the past versions information.

In general, we should take care of reviewing this page with every new release.

[szymontrocha]

Let's consider removing this menu item. This is currently an empty page https://www.perfsonar.net/collab_roadmap.html.
It's difficult to maintain and roadmap and plans are usually presented during presentations.