Qt6 port

I was wondering if the project had intention to track the progress towards using Qt6.

I believe that the approach that worked with other projects: trying to get it to build with Qt 5 and Qt6 at the same time. I would be happy to try and create granular issues for this and help out in any way that I can.

EDIT: Current state: Builds, is somewhat functional, but needs fixing. Major issues probably fixed in 3.2.0 (but Qt5 still recommended with 3.2.0)