Refactor Project Web Site to use Docsy

[csviri]

The current Jekyll template has more issue, it does not support links properly of sub section (and does not work sometimes), does not support sub section in menus, blog is not supported.

Docsy seems to support nicely all those features we require:

https://github.com/google/docsy
https://gohugo.io/hosting-and-deployment/hosting-on-github/

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[csviri]

done