(Reuters) - Hammerson Chief Executive Officer David Atkins will step down, the shopping mall owner and operator said on Wednesday, as it faces a crisis spurred by coronavirus-induced shop closures and a collapse in rent.The news comes just weeks after the owner of London's Brent Cross centre and the Bullring in Birmingham saw the collapse of its 400 million pound deal to sell seven retail parks to private equity firm Orion.Atkins, who has led the company for over a decade, will step down by..