Separate socket2 event for fullscreen (as opposed to maximize)

[sudoAlphaX]

Current socket2 event is the same fullscreen>>1 for both window maximizing event (fullscreen 1 dispatcher) and window fullscreen event (fullscreen 0 dispatcher). I request for a differentiator for these states.

Example use case:
Turn off keyboard backlight only during a fullscreen event (fullscreen 0 dispatcher): like watching a video in fullscreen.

[vaxerski]

#10472