Draft: Add more runtime dependencies

Based on https://bugs.kde.org/show_bug.cgi?id=486811, probably at least qml-module-qtwebengine could be added as it's runtime dependency for Wikipedia QML context applet. Likely also some other qml package that provides QtQuick.Controls 1, but I'm not sure which one that would be, and I don't have Neon installation handy to look up and confirm myself that easily, so submitting this MR just as partial draft and hoping that the answer is trivial to someone else.