PlasmaComponents 3 exists both as a theme for QQC2 but also to be used
directly like the current Plasma Components.
Currently they install into org.kde.plasma.components.3 which isn't a
valid path, also it doesn't include the qmldir, so you can't load it
This patch installs the files to a subdir of org.kde.plasma.components
then update the original root qmldir toload the QQC2 version if the