Add modifiers to the tile-drag to add functionality

Submitted by Harold Aling

Assigned to Olivier Fourdan @olivier

Link to original bug (#11117)

Description

What about adding modifiers to the tile-drag functionality?

How I would like the tile feature to behave:

1. Shift-drag* (any) window to the left/right/top/bottom of a screen tiles it to the left/right/top/bottom half.
2. Drag without modifier does nothing but drag.
3. Drag a maximized window stays the same: drag to top on another screen and it will stay maximized
4. Drag an un-maximized window to the top and it will maximize

*) This should be a preference: shift/ctrl/alt/super. Maybe even an inverse-option: use a modifier to do nothing but drag.