Fitts's law fix for all controls

[ghost]

As part of the latest design, buttons often have a space around them. This causes issues when buttons are placed on the edge of the screen, because it's harder to reach them (see Fitts's law and #5306).
The solution for this is to make the button hitbox larger than the actual visual of the button, like CommandBar buttons.

This functionality should be expanded to more controls.

There are two ways this could be achieved:

• An InnerMargin property for most controls
• A property that changes how margins are applied (Inner/Outer)