Get rid of the hamburger menu or make it more useful

[Neui]

At the top right there would be pages you can jump to (navigation), but I removed it because it added all pages and I don't think it is really needed at that point while migrating from the wiki.

getting-things-gnome.github.io/_includes/header.html

Line 27 in 71a6ae7

<!-- Just nothing at the moment -->

However, on mobile the hamburger menu is still visible, but does nothing: