separate plugin ui & make Pilz.Plugins.Advanced package platform independent

Pilz.Plugins.Advanced.UI/FeatureInsertPosition.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Pilz.Plugins.Advanced.UI
+{
+    [Flags]
+    public enum FeatureInsertPosition
+    {
+        None = 0,
+        Default = 1,
+        Top = 2,
+        Bottom = 3,
+    }
+}