Add converting primitives and calculators

StructureHelperCommon/Infrastructures/Interfaces/IHasForceActions.cs

@@ -0,0 +1,13 @@
+using System.Collections.Generic;
+using StructureHelperCommon.Models.Forces;
+
+namespace StructureHelperCommon.Infrastructures.Interfaces
+{
+    public interface IHasForceActions
+    {
+        /// <summary>
+        /// Collection of force actions
+        /// </summary>
+        List<IForceAction> ForceActions { get; }
+    }
+}