Switch the Wayland greeter default to use Weston's Kiosk shell

[Conan-Kudo]

Weston introduced the kiosk shell in Weston 9.0 and deprecated the fullscreen shell in Weston 12.0.

[Conan-Kudo]

I've marked this as draft because I don't know how we want to handle this. My understanding is that this functionality does not work properly in Qt 5 without the KDE patch set. If we're fine with assuming that it will be built against and run with Qt 5 only with the KDE Patch Collection applied, then we can land this now. Otherwise we have to wait until we strip out Qt 5 support and go Qt 6-only.

cc: @fooishbar, @davidedmundson

[Vogtinator]

I've marked this as draft because I don't know how we want to handle this. My understanding is that this functionality does not work properly in Qt 5 without the KDE patch set.

In which way?

[Conan-Kudo]

I don't remember exactly where I read it, but apparently xdg-toplevel on xdg-shell doesn't work properly with QtWayland without the KDE Patch Collection?

[Conan-Kudo]

Ah, here's where I saw it. It was a comment by @davidedmundson here: #1393 (comment)

[Vogtinator]

Ok. IMO checking the Qt version during buildtime is close enough, let's just assume that any distro with Qt >= 5.15.10 uses the patch collection?

[Conan-Kudo]

Yeah, I would say so.

[fooishbar]

Yeah the Weston patch is great, thanks.

[Conan-Kudo]

@Vogtinator can we land this, please? Weston is working to remove fullscreen shell, and this is the only user of it I can find in Fedora.