keyboard navigation in and out QML kcms
Summary:
QQuickWidget doesn't support keyboard navigation per se,
the widget will gain keyboard focus on tab, but lose it again at
the next tab press. this manages manually tab and backtab in the widget
with an event filter, using an heuristic to know when the tab focus reached
the last qtquick component and should go out focusing the next widgets
Test Plan:
keyboard navigation with tab/shift+tab works as expected
both in systemsettings and kcmshell5
Reviewers: Plasma, Frameworks, davidedmundson
Reviewed By: Plasma, davidedmundson
Subscribers: broulik, davidedmundson, ngraham, plasma-devel, Frameworks
Tags: Plasma, Frameworks
Differential Revision: https://phabricator.kde.org/D8522