Target’s massive data breach has now cost the company's CEO his job. Target announced Monday that Chairman, President and CEO Gregg Steinhafel is out nearly five months after the retailer disclosed the breach, which has hurt its reputation among customers and has derailed its business. […] Steinhafel’s tenure has been tested with many challenges, from a weak economy to a proxy fight. The company, known for its cheap chic clothing and home decor, has seen uneven sales since the recession ended and has battled a perception that its prices aren’t as low as its rivals. …