Add roadmap to website

[Kreolis]

https://github.com/orgs/overte-org/projects/3

Best way linking. Is there some integration we could do? Automatic image gen?

[Kreolis]

Could this be interesting?
https://github.com/wustep/github-project-exporter

[IF-Adin]

CSV is a bit meh, but i will look into a way of doing it.

[JulianGro]

Just food for thought: We could replace GitHub with Strapi for the roadmap.

Right now we don't really use any GitHub (or generally code forge) specific feature for the roadmap, except for authentication (as in who can edit the roadmap).