Implement worker AddItem commands

src/MxGateway.Worker/MxAccess/RegisteredItemHandle.cs

@@ -0,0 +1,28 @@
+namespace MxGateway.Worker.MxAccess;
+
+public sealed class RegisteredItemHandle
+{
+    public RegisteredItemHandle(
+        int serverHandle,
+        int itemHandle,
+        string itemDefinition,
+        string itemContext,
+        bool hasItemContext)
+    {
+        ServerHandle = serverHandle;
+        ItemHandle = itemHandle;
+        ItemDefinition = itemDefinition;
+        ItemContext = itemContext;
+        HasItemContext = hasItemContext;
+    }
+
+    public int ServerHandle { get; }
+
+    public int ItemHandle { get; }
+
+    public string ItemDefinition { get; }
+
+    public string ItemContext { get; }
+
+    public bool HasItemContext { get; }
+}