Add polygon to DTO convert strategy

StructureHelperCommon/Models/Shapes/IPolygonSegment.cs

@@ -0,0 +1,11 @@
+using StructureHelperCommon.Infrastructures.Interfaces;
+
+namespace StructureHelperCommon.Models.Shapes
+{
+    public interface IPolygonSegment : ISaveable
+    {
+        IVertex StartVertex { get; }
+        IVertex EndVertex { get; }
+        void UpdateEndFromParameters();
+    }
+}