inputmethod&plugins/buttonrebinds: use new KKeyServer API
To correctly handle Qt::Key_Calculator corresponding to both XF86Calculator and XF86Calculater.
Depends on frameworks/kwindowsystem!145 (merged)
Unfortunately I the ButtonRebinds KCM doesn't even open for me in x11, so I was not able to test that. It would be great if someone could help test that you can bind Calculator key! @teams/qa