Add import of polygon from dxf

StructureHelperCommon/Services/Exports/IImportLogic.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StructureHelperCommon.Services.Exports
+{
+    public interface IImportLogic
+    {
+        void Import();
+    }
+}