Pass a widget when invoking `QStyle::drawControl()`; the Windows 11 style
uses the widget unconditionally.
Considering the documentation explicitly states `The widget argument is
optional` and the default value for the function argument is `nullptr` this
is supposedly a bug in Qt.
* Avoid multiple definitions of `centerObj()`; this was very bad anyway
* Include `c++utilities/tests/testutils.h` upfront so the formatting
operators are included before CppUnit
* Use the name as sorting criteria and fall back to the ID if there's no
name
* Use new SyncthingSortFilterDirectoryModel also for Plasmoid's filtering
* See https://github.com/Martchus/syncthingtray/issues/75
* Support triggering actions via the context menu in the regular tray like
it is already possible in the Plasmoid
* Support copying via the context menu in the Plasmoid like it is already
possible in the regular tray
* Reduce repetition of coding patterns using templates
Martchus