This runner allows to find all Plasma widgets and adds them to the desktop.

Suggested by Eike. The widget is added to the desktop where the mouse is (was easiest solution as a runner doesn't know (and shouldn't) where the krunner window is but this is close enough). The widget can also be dragged from krunner to anywhere (eg. to a panel).

The code is adapted from the windowed widgets runner and perhaps we could merge the two, even.

There's a bit of an overlap if I eg serach "Calculator" I get "Add Widget: Calculator" and "Windowed Widget: Calculator" but if we merge the two with action button it will be inconsistent if an applet does *not* offer standalone mode :/

Todo:

• The script is hardcoded in the c++ file and then sent on dbus, dunno, could be saved to a different file but I wanted to save me the trouble with cmake and qstandardpaths.
• It does not check whether widgets are locked (how can I do that?) because then it would just do nothing
• The priority/relevance level might need tweaking

Video: https://www.youtube.com/watch?v=p9sLzX-SCE0