Added INavigationService interface

Author: szv

src/Codebreaker.ViewModels/Contracts/Services/INavigationService.cs

@@ -0,0 +1,10 @@
+namespace Codebreaker.ViewModels.Contracts.Services;
+
+public interface INavigationService
+{
+    bool CanGoBack { get; }
+
+    ValueTask<bool> NavigateToAsync(string key, object? parameter = null, bool clearNavigation = false);
+
+    ValueTask<bool> GoBackAsync();
+}