deprecate(lmxproxy): move all LmxProxy code, tests, and docs to deprecated/

LmxProxy is no longer needed. Moved the entire lmxproxy/ workspace, DCL
adapter files, and related docs to deprecated/. Removed LmxProxy registration
from DataConnectionFactory, project reference from DCL, protocol option from
UI, and cleaned up all requirement docs.

deprecated/lmxproxy/src-reference/ZB.MOM.WW.LmxProxy.Client/LmxProxyClient.ISubscription.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Threading.Tasks;
+
+namespace ZB.MOM.WW.LmxProxy.Client
+{
+    /// <summary>
+    /// Represents a subscription to tag value changes
+    /// </summary>
+    public interface ISubscription : IDisposable
+    {
+        /// <summary>
+        /// Disposes the subscription asynchronously
+        /// </summary>
+        Task DisposeAsync();
+    }
+}