Add settings for autostack

[ppvolto]

I love that i can replace Gnome now, but one thing is missing the old autostacking behavior in tiling.

Currently i need to enable stacking for the first application on a workspace to get the same functionality.

I like tiling but i miss the default autostacking and possible the reordering of stacked items.

[educbraga]

Hi! Regarding the reordering of stacked items, the shortcut Super + Shift + Right or Left Arrow does this.