Pr3/carousel page (#772)

* feat: add CarouselPage and PipsPager.

* feat: add PipsPager control and integrate into index

* feat: add PipsPagerDemo and integrate into MainView

---------

Co-authored-by: Zhang Dian <54255897+zdpcdt@users.noreply.github.com>

demo/Semi.Avalonia.Demo/Pages/CarouselPageDemo.axaml.cs

@@ -0,0 +1,34 @@
+using System.Collections;
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+
+namespace Semi.Avalonia.Demo.Pages;
+
+public partial class CarouselPageDemo : UserControl
+{
+    public CarouselPageDemo()
+    {
+        InitializeComponent();
+    }
+
+    private void OnPrevious(object? sender, RoutedEventArgs e)
+    {
+        if (DemoCarousel.SelectedIndex > 0)
+            DemoCarousel.SelectedIndex--;
+    }
+
+    private void OnNext(object? sender, RoutedEventArgs e)
+    {
+        var pageCount = (DemoCarousel.Pages as IList)?.Count ?? 0;
+        if (DemoCarousel.SelectedIndex < pageCount - 1)
+            DemoCarousel.SelectedIndex++;
+    }
+
+    private void OnSelectionChanged(object? sender, PageSelectionChangedEventArgs e)
+    {
+        if (StatusText == null)
+            return;
+        var pageCount = (DemoCarousel.Pages as IList)?.Count ?? 0;
+        StatusText.Text = $"Page {DemoCarousel.SelectedIndex + 1} of {pageCount}";
+    }
+}