Adding full DI navigation example for testing purposes.

- adding internal private field into FormBase class
- adding Extension methods into DependencyInjection namespace for use
- adding 2 NavigateTo extension methods for DI using ServiceProvider
- adding example project
- adding to readme as example

TelegramBotBase/Base/FormBase.cs

@@ -32,6 +32,8 @@ public class FormBase : IDisposable
 
     public MessageClient Client { get; set; }
 
+    IServiceProvider _serviceProvider = null;
+
     /// <summary>
     ///     has this formular already been disposed ?
     /// </summary>