Improves and cleans up TabletopSystem further. (#4633)

Content.Server/Tabletop/TabletopSetup.cs

@@ -1,5 +1,4 @@
 using Robust.Shared.GameObjects;
-using Robust.Shared.Map;
 using Robust.Shared.Serialization.Manager.Attributes;
 
 namespace Content.Server.Tabletop
@@ -7,6 +6,12 @@ namespace Content.Server.Tabletop
     [ImplicitDataDefinitionForInheritors]
     public abstract class TabletopSetup
     {
-        public abstract void SetupTabletop(MapId mapId, IEntityManager entityManager);
+        /// <summary>
+        ///     Method for setting up a tabletop. Use this to spawn the board and pieces, etc.
+        ///     Make sure you add every entity you create to the Entities hashset in the session.
+        /// </summary>
+        /// <param name="session">Tabletop session to set up. You'll want to grab the tabletop center position here for spawning entities.</param>
+        /// <param name="entityManager">Dependency that can be used for spawning entities.</param>
+        public abstract void SetupTabletop(TabletopSession session, IEntityManager entityManager);
     }
 }