Job adverts hint at its imminent arrival but Tesla is yet to confirm recent reports that it will set up a new electric vehicle (ev) “gigafactory” in Monterrey, a Mexican city close to the American frontier. The rumours have nonetheless set wheels in motion. Noah Itech, a Chinese supplier of automation equipment to the American car company, is building a $100m plant in the city. If Elon Musk’s firm sets up in Mexico it will be the latest…