Port KTimeTracker to Qt6
This is a port of KTimeTracker to Qt6/KF6.
- Code was ported to Qt6/KF6
- CMake now requires strictly Qt6/KF6
- kdesrc-build dependencies were bumped to latest-kf6
- Only CI for Linux/FreeBSD available as it's not something I can fix right now
Edited by Thiago Sueto