By Tom Sims, Frank Siebelt and Paul Carrel FRANKFURT (Reuters) -The chief executive of top German asset manager DWS will step down next week, he said on Wednesday, a day after raids by prosecutors over allegations that the company misled investors about “green” investments. The raids and departure of DWS CEO Asoka Woehrmann mark another setback for Deutsche Bank, DWS’s majority owner, which has been trying to move on from regulatory breaches, including money laundering and securities misselling, leading to billions in fines. DWS has been dogged by the accusations for months, prompting German p…