[Blazor] Analyzer for detecting basic cycles in Layout components

If you put a `@Layout MyLayout` directive inside an `_Imports.razor` and `MyLayout.razor` is defined in a subfolder of that folder, you end up with something like this:

```
[Layout(MyLayout)]
public class MyLayout : LayoutBase
{
}
```

Creating an infinite rendering loop. We don't want to anything at runtime, but we can do something at compile time to detect this scenario.