[applets/systemtray] Refactor systemtray
Major refactoring of SystemTray logic, mainly around Applets/Plasmoids lifecycle. It is now more event based.
BUG: 424230 FIXED-IN: 5.21.0
Major refactoring of SystemTray logic, mainly around Applets/Plasmoids lifecycle. It is now more event based.
BUG: 424230 FIXED-IN: 5.21.0