UI: Option to automatically Hide UI when game launches

Quality of life feature
Similar in function to the "Start Games in Fullscreen" toggle
For users who want to run games in windowed/non-fullscreen mode with
menu UI hidden, this eliminates the need to always click "Hide UI"

src/Ryujinx/UI/ViewModels/MainWindowViewModel.cs

@@ -922,6 +922,19 @@ namespace Ryujinx.Ava.UI.ViewModels
             }
         }
 
+        public bool StartGamesWithoutUI
+        {
+            get => ConfigurationState.Instance.UI.StartNoUI;
+            set
+            {
+                ConfigurationState.Instance.UI.StartNoUI.Value = value;
+
+                ConfigurationState.Instance.ToFileFormat().SaveConfig(Program.ConfigurationPath);
+
+                OnPropertyChanged();
+            }
+        }
+
         public bool ShowConsole
         {
             get => ConfigurationState.Instance.UI.ShowConsole;
@@ -1649,6 +1662,11 @@ namespace Ryujinx.Ava.UI.ViewModels
             StartGamesInFullscreen = !StartGamesInFullscreen;
         }
 
+        public void ToggleStartGamesWithoutUI()
+        {
+            StartGamesWithoutUI = !StartGamesWithoutUI;
+        }
+
         public void ToggleShowConsole()
         {
             ShowConsole = !ShowConsole;