Grid Navigation for Sectionbox Navigator

[Wurschdhaud]

Is your feature request related to a problem? Please describe

as disussed in #2881 grid navigation would be nice

Describe the solution you'd like

Describe alternatives you've considered

Additional context

[Wurschdhaud]

Progress...

progress.grid.navigation.mp4

Working so far.
By now the code is unfortunately quite messy AI spaghetti. I'll try to clean it up before the PR.