Baltimore City Fire Department via ReutersAuthorities are ending a search-and-rescue mission for six contractors who they believe were plunged into the icy cold waters of the Patapsco River early Tuesday morning when a container ship lost power and slammed into a pillar supporting Baltimore’s Francis Scott Key Bridge.“Based on the length of time that we have gone in this search, the extensive search efforts that we have put into it, the water temperature, at this point we do not believe that we’