port ViewDebugger

[Xiaoy312]

What would you like to be added:

unoplatform/uno.extensions@main/src/Uno.Extensions.Reactive.UI/Utils/ViewDebugger

Why is this needed:

For which Platform:

• iOS
• Android
• WebAssembly
• WebAssembly renders for Xamarin.Forms
• Windows
• Build tasks

Anything else we need to know?

add [Conditional("DEBUG")] on the setters

[Xiaoy312]

summary:
contract:

• as-is;

•   ViewDebugger
    	.IsEnabled = (bool)					// flag to active: AvailableVisualStates and CurrentVisualStates
    	.AvailableVisualStates = (string)	// [get-only] list the available visual-states defined in the ControlTemplate or the template root.
    		^ eg: "CommonStates: Normal, PointerOver, Pressed, Disabled; FocusStates: Focused, PointerFocused, Unfocused;"
    	.CurrentVisualStates = (string)		// semi-colon-separated list of active state in each of defined VisualStateGroup; can be set to force a control to enter specific state
    		^ eg: "Disabled;Unfocused", "Disabled" (only update the CommonStates)