Right now we have 24px monochrome icons for compatibility with GTK apps, which use icons
of this size. However they are visually identical to the 22px versions, with one pixel of
padding on all sides. Manually creating them is tedious busywork.
This patch automatically generates 24px monochrome icons from the 22px versions for
action, device, places, and status icons by editing the SVG files to increase the size
of the viewbox and apply a (1,1) translation to the content.
That way I implemented this seems to work pretty reliably on the icon generation side.
However I am less sure about how it is integrated into the CMake files. It works, but if
I did it wrong, let me know.