And make mousebind handlers use that one.
Also remove keyboard_any_modifiers_pressed() and replace its usage
with the new function.
Without this patch we would only request the modifier state of the
keyboard group which makes mousebinds involving keyboard modifiers
break for virtual keyboards like when using wayvnc. Same story for
hiding the workspace overlay or snapping to regions.
Fixes: #2511
Applies drag resistance unidirectionally for horizontally/vertically
maximized windows, allowing them to be dragged without being untiled
immediately. When the distance of cursor movement orthogonal to the
maximized direction exceeds <resistance><unMaximizeThreshold>.
While dragging a horizontally/vertically maximized window, edge/region
snapping is disabled to prevent unintentional snapping and overlays.
This commit also includes some refactoring to simplify the logic.
...and unify region overlay and snap-to-edge overlay into overlay.c.
Snap-to-edge overlay is delayed for 500ms to prevent flickering when
the view is dragged from an output to another (demo in discussion labwc#1613).
This also fixes a bug that region overlay is not shown when a modifier
key is re-pressed.
When wanting to snap to a region when starting the move
operation with A-Left (or a similar mousebind which includes a
modifier), the modifier - or another one - must be pressed again.
Fixes#761
