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/ZB.MOM.WW.LmxProxy.Client/Domain/ConnectionState.cs

@@ -0,0 +1,12 @@
+namespace ZB.MOM.WW.LmxProxy.Client.Domain;
+
+/// <summary>Represents the state of a connection to the LmxProxy service.</summary>
+public enum ConnectionState
+{
+    Disconnected,
+    Connecting,
+    Connected,
+    Disconnecting,
+    Error,
+    Reconnecting
+}