Adds parchís game board, improves tabletop system to support other games. (#4610)

Content.Server/Tabletop/TabletopSetup.cs

@@ -0,0 +1,12 @@
+using Robust.Shared.GameObjects;
+using Robust.Shared.Map;
+using Robust.Shared.Serialization.Manager.Attributes;
+
+namespace Content.Server.Tabletop
+{
+    [ImplicitDataDefinitionForInheritors]
+    public abstract class TabletopSetup
+    {
+        public abstract void SetupTabletop(MapId mapId, IEntityManager entityManager);
+    }
+}