Remove qtquickcontrols dir
Summary: @mart said these files are no longer used, so I'm removing them.
Reviewers: Breeze, Plasma, davidedmundson
Reviewed By: Plasma, davidedmundson
Subscribers: apol, davidedmundson, mart, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D21969