Include Elements Csharp - Uno

Update the StackPanel to remove the HorizontalAlignment property, as we'll be centering each of the nested elements individually.
csharp
```
new StackPanel()
    .VerticalAlignment(VerticalAlignment.Center)
```

Update the Image element to center it horizontally and add a margin.

csharp

new Image()
    .Margin(12)
    .HorizontalAlignment(HorizontalAlignment.Center)
    .Width(150)
    .Height(150)
    .Source("ms-appx:///Assets/logo.png"),

Add a TextBox to allow the user to enter the step size.

csharp

new TextBox()
    .Margin(12)
    .HorizontalAlignment(HorizontalAlignment.Center)
    .TextAlignment(Microsoft.UI.Xaml.TextAlignment.Center)
    .PlaceholderText("Step Size")
    .Text("1"),

Add a TextBlock to display the current counter value.

csharp

new TextBlock()
    .Margin(12)
    .HorizontalAlignment(HorizontalAlignment.Center)
    .TextAlignment(Microsoft.UI.Xaml.TextAlignment.Center)
    .Text("Counter: 1"),

Add a Button to increment the counter.

csharp

new Button()
    .Margin(12)
    .HorizontalAlignment(HorizontalAlignment.Center)
    .Content("Increment Counter by Step Size")