General settings: Put all advanced checkboxes in a layout

General settings: Put all advanced checkboxes in a layout

The mac style has the concept of Layout Item Rectangle that bleeds
widgets margins into parent margins. This unfortunately doesn't work
when the parent layout doesn't have any margin, like we do when we
have the hierarchy:
 Vertical(normal margin)
   / Horizontal(no margin, uses parent layout spacing)
     /Widget

I guess Qt should propagate remaining uneaten margins to grand-parent
layouts and so on to have this work properly, but nobody seems to
have touched that code since Qt 4.4.
So just try to make the problem less worse by making sure that
all checkboxes we want to align are either in the same layout, or
in a loyout of their own.

Issue #5492