Added an update rule for DomainIndex removal

Also for adding the new HPF-related PathFinderOverlay and HierarchicalPathFinderOverlay that were added at the same time.

OpenRA.Mods.Common/UpdateRules/Rules/20210321/RemoveDomainIndex.cs

@@ -0,0 +1,33 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+
+namespace OpenRA.Mods.Common.UpdateRules.Rules
+{
+	public class RemoveDomainIndex : UpdateRule
+	{
+		public override string Name => "Remove DomainIndex from World and add path finder overlays.";
+
+		public override string Description => "The DomainIndex trait was removed from World. Two overlay traits were added at the same time.";
+
+		public override IEnumerable<string> UpdateActorNode(ModData modData, MiniYamlNode actorNode)
+		{
+			if (actorNode.RemoveNodes("DomainIndex") > 0)
+			{
+				actorNode.AddNode(new MiniYamlNode("PathFinderOverlay", ""));
+				actorNode.AddNode(new MiniYamlNode("HierarchicalPathFinderOverlay", ""));
+			}
+
+			yield break;
+		}
+	}
+}

OpenRA.Mods.Common/UpdateRules/UpdatePath.cs

@@ -96,6 +96,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 				new UnhardcodeBaseBuilderBotModule(),
 				new UnhardcodeVeteranProductionIconOverlay(),
 				new RenameContrailProperties(),
+				new RemoveDomainIndex(),
 			}),
 
 			new UpdatePath("playtest-20221203", new UpdateRule[]