community/kde*: upgrade to 6.0.0

Still needs Discover's apk integration ported to Plasma 6. Also Plasma Bigscreen and it's applications are not part of this release yet and I can't really easily keep them without not keeping the rest of Plasma on 5 as well, so these are dropped for now (I'll reintroduce them when they're available again).

CI takes too long to compile it all so I'm building it all locally (just for x86_64) and once it's all done I'll merge this.