This patch implements two new margins for the panel: a standard one, used by default on all widgets, and a slim one. The slim one is to be used by widgets whose icon needs to be a bit bigger on smaller panels, such as the task manager and the app launcher.
See also:
plasma/plasma-desktop!92 (merged)
plasma/plasma-desktop!128 (closed)
This, along with the other patches, is the result:
