Some apps may not support printing only a particular page range, but
with CUPS we can do "server-side print range", ie. we can select the
page range for the application.

If CUPS is available, the Page Range widget is now displayed if app
advertises no such capability and page range is selected on the server
instead.

[ChangeLog][QtPrintSupport][QPrintDialog] Added CUPS server-side print
range support for apps that can't support print range option themselves

Change-Id: Ia7784065ba5a8b53bb05ae46e982c718ef672fa5
Reviewed-by: John Layt <jlayt@kde.org>