Add setting for zone hit testing to be less aggressive

[enricogior]

• Agree with Ranjesh that the snapping feels too aggressive, I kinda want to have to be near the center of the zone to snap into it, so that if my mouse is near an edge of a zone it doesn’t get “sucked into the well of gravity” if that makes sense. If I grab a window by the right half of the title bar, and drag it around, it is easy to end up with my mouse pointer inside a region when the top-left of the window is not, and then I have to drag the window too far left to avoid it going where I didn’t mean it to. Maybe an option to have the zone be determined by the window’s upper-left instead of the mouse position would feel more like what I want?

[enricogior]

Closing this in favor of the #1167