* Added ReplyKeyboardMarkupGenerator

* Added set of markup attributes dedicatedf to map a keyboard using partial methods

dev/Telegrator.RoslynExtensions/StringBuilderExtensions.cs

@@ -0,0 +1,10 @@
+using System.Text;
+
+namespace Telegrator.RoslynExtensions
+{
+    public static class StringBuilderExtensions
+    {
+        public static StringBuilder AppendTabs(this StringBuilder builder, int count)
+            => builder.Append(new string('\t', count));
+    }
+}