Core/Game: Move scheduled map scripts counter methods into MapManager

* Since those have nothing to do with core scripts and are
  not wished inside the ScriptMgr

src/server/game/Maps/Map.cpp

@@ -64,7 +64,7 @@ Map::~Map()
     }
 
     if (!m_scriptSchedule.empty())
-        sScriptMgr->DecreaseScheduledScriptCount(m_scriptSchedule.size());
+        sMapMgr->DecreaseScheduledScriptCount(m_scriptSchedule.size());
 
     MMAP::MMapFactory::createOrGetMMapManager()->unloadMapInstance(GetId(), i_InstanceId);
 }