Change install location of kstyle config plugin
Currently the plugin is installed to /plasma/kcms/systemsettings_qwidgets, which is odd considering it's not a stanalone KCM that's supposed to be loaded by systemsettings directly
Instead it's loaded by the style KCM
Technically the exact location doesn't matter because the full path relative to the plugin dir is specified, so move it to a more appropriately named location