KDE: Add KDE Frameworks 6 ports

KDE's 6th Megarelease - Alpha

Wednesday, 8 November 2023

En route to the new Plasma, Frameworks and Gear

Every few years we port the key components of our software to a new
version of Qt, taking the opportunity to remove cruft and leverage the
updated features the most recent version of Qt has to offer us.

It has been nearly 10 years since the last big release of our flagship
Plasma desktop environment, and the time has come again. KDE is making
available today the Alpha version of all the software we will include in
a megarelease scheduled for the end of February 2024.

Announcement: https://kde.org/announcements/megarelease/6/alpha/
Obtained from:	https://github.com/tcberner/kde6-overlay/

Further ports specific changes:
 * multimedia/phonon: is now flavored for Qt5 and Qt6