Add support for Fullscreen UI in Moonlight (#492)

* initial UI and window decoration removal toggle

* revert default height change

* add fullscreen support to kiosk mode

* add tool tip for kiosk mode

* change to fullscreen rather than kiosk

* update to Fullscreen instead of Full-screen or Full Screen

* update UI text

* convert to display mode picker

* add UI label for picker

* clean up references to startMaximized and fullScreenUIMode

* remove flags property, as fullscreen visiblity handles this already

* use Maximized in selection text

* account for running moonlight without a window manager

* lock display mode from being changed if there is no window manager running

Co-authored-by: jmt-gh <jmt-gh@users.noreply.github.com>

app/gui/main.qml

@@ -17,8 +17,16 @@ ApplicationWindow {
     width: 1280
     height: 600
 
-    visibility: (SystemProperties.hasWindowManager && StreamingPreferences.startWindowed) ? "Windowed" : "Maximized"
-
+    visibility: {
+        if (SystemProperties.hasWindowManager) {
+            if (StreamingPreferences.uiDisplayMode == StreamingPreferences.UI_WINDOWED) return "Windowed"
+            else if (StreamingPreferences.uiDisplayMode == StreamingPreferences.UI_FULLSCREEN_WINDOWED) return "Maximized"
+            else if (StreamingPreferences.uiDisplayMode == StreamingPreferences.UI_FULLSCREEN) return "FullScreen"
+        } else {
+            return "Maximized"
+        }
+    }
+  
     // This configures the maximum width of the singleton attached QML ToolTip. If left unconstrained,
     // it will never insert a line break and just extend on forever.
     ToolTip.toolTip.contentWidth: ToolTip.toolTip.implicitContentWidth < 400 ? ToolTip.toolTip.implicitContentWidth : 400