BERLIN (Reuters) - The head of human resources at Adidas has stepped down after a group of employees called for an investigation over her handling of racism at the company which she had described last year as "noise" only discussed in America.The German sportswear company said that Karen Parkin was leaving the company after 23 years in mutual agreement with the supervisory board effective June 30, with Chief Executive Kasper Rorsted taking over her role on an interim basis."Her decision to..