Option to toggle the system tray icon (#23220)

* Added option to toggle the system tray icon

At the moment, this hides the icon making the settings window inaccessible without first modifying the general `settings.json` file.

* Use IPC messages to manage the tray icon settings

* Fix launching second window binds to active settings process

* Added context menu option to hide tray icon

* Added Exit PT button to settings ui NavigationView.PaneFooter

* Moved DllImports to NativeMethods.cs

* Sentence case titles

* Fix whitespace

* Re-add exit icon to NavView

* Re-added toggle switch to new UI

* Fix build

* Fix build after merge main

* Fix the string to display

* add shut down buttons

* finish polish

* fix string

* Styling tweaks to titlebar and settingscards

* fix comment

* fix unit test

* fix ut

---------

Co-authored-by: Jaime Bernardo <jaime@janeasystems.com>
Co-authored-by: vanzue <vanzue@outlook.com>
Co-authored-by: Kayla Cinnamon <cinnamon@microsoft.com>
Co-authored-by: Niels Laute <niels.laute@live.nl>

src/settings-ui/Settings.UI/SettingsXAML/Views/ShellPage.xaml

@@ -39,10 +39,17 @@
             Margin="48,0,0,0"
             VerticalAlignment="Top"
             IsHitTestVisible="True">
+            <Grid.ColumnDefinitions>
+                <ColumnDefinition x:Name="LeftTitleBarColumn" Width="*" />
+                <ColumnDefinition x:Name="RightTitleBarColumn" Width="Auto" />
+            </Grid.ColumnDefinitions>
             <animations:Implicit.Animations>
                 <animations:OffsetAnimation Duration="0:0:0.3" />
             </animations:Implicit.Animations>
-            <StackPanel Orientation="Horizontal">
+            <StackPanel
+                Grid.Column="0"
+                HorizontalAlignment="Left"
+                Orientation="Horizontal">
                 <Image
                     Width="16"
                     Height="16"
@@ -64,6 +71,24 @@
                     TextWrapping="NoWrap"
                     Visibility="Collapsed" />
             </StackPanel>
+            <StackPanel
+                Grid.Column="1"
+                Margin="0,0,148,0"
+                HorizontalAlignment="Right"
+                Orientation="Horizontal">
+                <Button
+                    x:Name="ShutDownBtn"
+                    Height="48"
+                    Click="ExitPTItem_Tapped"
+                    Style="{StaticResource SubtleButtonStyle}">
+                    <FontIcon FontSize="16" Glyph="&#xE7E8;" />
+                    <ToolTipService.ToolTip>
+                        <ToolTip>
+                            <TextBlock x:Uid="AppTitleBarShutDown_Tooltip" />
+                        </ToolTip>
+                    </ToolTipService.ToolTip>
+                </Button>
+            </StackPanel>
         </Grid>
         <NavigationView
             x:Name="navigationView"