Migrate to Qt 6

[Liya-q]

@faveoled could you please help me with that? :)

[faveoled]

I think it's blocked
ubuntu/snapcraft-desktop-helpers#227

[Liya-q]

Looks like snapcraft-desktop-helpers is deprecated

ℹ️ We are currently in the process of moving most of the functionality of the desktop helpers to Snapcraft Extensions. The extensions are much easier to use and contain many improvements, so it's advised to use an extension if one is available for the GUI toolkit that you use.

so we need to use Snapcraft Extensions
https://forum.snapcraft.io/t/snapcraft-extensions/13486
https://forum.snapcraft.io/t/supported-extensions/20521

I think kde-neon-6 is good choice here, however it does not support core24 (yet)

[Liya-q]

https://forum.snapcraft.io/t/rfc-migrating-gnome-and-kde-snapcraft-extensions-to-gpu-2404-userspace-interface/39718