Refactor map loading & saving

Content.Server/GameTicking/Rules/Components/LoadMapRuleComponent.cs

@@ -20,11 +20,17 @@ public sealed partial class LoadMapRuleComponent : Component
     public ProtoId<GameMapPrototype>? GameMap;
 
     /// <summary>
-    /// A map path to load on a new map.
+    /// A map to load.
     /// </summary>
     [DataField]
     public ResPath? MapPath;
 
+    /// <summary>
+    /// A grid to load on a new map.
+    /// </summary>
+    [DataField]
+    public ResPath? GridPath;
+
     /// <summary>
     /// A <see cref="PreloadedGridPrototype"/> to move to a new map.
     /// If there are no instances left nothing is done.