Desktop scripting: support args
Summary:
support args in applet creation with an optional argument to
containment::addWidget
scripts not using it will continue to work as before
Test Plan:
arguments get understood byt the created applet
applets can still be created without arguments
Reviewers: Plasma, broulik
Reviewed By: Plasma, broulik
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D22652