Require and use the new NewStuffQuick Button component
This removes the need for the custom hack for spawning a dialog,
and is intended to function as a sample for how to implement this
in other KCMs.
Also use the big, pretty Preview mode (because super-visual content)
This could be done wholesale for the entire bunch of KCMs, but i post
this on its own in an attempt to gain feedback on a self contained
example of how to do this porting step.
Without this patch:
With this patch:
Depends on D25041
Reviewed By: VDG, ngraham
Subscribers: ngraham, plasma-devel
Differential Revision: https://phabricator.kde.org/D24942