A delivery worker with a backpack of Deliveroo rides a bike in Nice, France, October 25, 2022. REUTERS/Eric Gaillard/File Photo Purchase Licensing Rights, opens new tabCompaniesSept 18 (Reuters) - British food delivery firm Deliveroo (ROO.L), opens new tab said on Thursday founder and CEO Will Shu will step down once its takeover by U.S. rival DoorDash takes effect.U.S. meal delivery firm DoorDash in May agreed to buy Deliveroo in a deal valuing the British rival at about 2.9 billion pounds ($3...