Adding StateMachine for Session serialization

- adding multiple classes and interfaces for Session Serialization and recovery after restart

TelegramBotBase/Interfaces/IStateForm.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using TelegramBotBase.Args;
+using TelegramBotBase.Base;
+
+namespace TelegramBotBase.Interfaces
+{
+    /// <summary>
+    /// Is used to save specific fields into a session state to survive restarts or unhandled exceptions and crashes.
+    /// </summary>
+    public interface IStateForm
+    {
+
+        void LoadState(LoadStateEventArgs e);
+
+        void SaveState(SaveStateEventArgs e);
+
+    }
+}

TelegramBotBase/Interfaces/IStateMachine.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using TelegramBotBase.Args;
+using TelegramBotBase.Base;
+
+namespace TelegramBotBase.Interfaces
+{
+    public interface IStateMachine
+    {
+        void SaveFormStates(SaveStatesEventArgs e);
+
+        StateContainer LoadFormStates();
+    }
+}