Add quit-app-and-exit shortcut Ctrl+Alt+Shift+E

Add a shortcut to quit the current app and exit Moonlight entirely.

app/streaming/input/input.h

@@ -164,6 +164,7 @@ private:
         KeyComboToggleMinimize,
         KeyComboPasteText,
         KeyComboTogglePointerRegionLock,
+        KeyComboQuitAndExit,
         KeyComboMax
     };