By Julia Love and Helen Coster (Reuters) -Donald Trump’s new social media venture, Truth Social, appears set to launch in Apple’s App Store on Monday, according to posts from an executive on a test version viewed by Reuters, potentially marking the return of the former president to social media on the U.S. Presidents Day holiday. In a series of posts late on Friday, a verified account for the network’s chief product officer, listed as Billy B., answered questions on the app from people invited to use it during its test phase. One user asked him when the app, which has been available this week …