ENGLEWOOD — Greg Maffei is stepping down as president and chief executive of Liberty Media, the company that owns Formula 1. Liberty Media said Wednesday that Maffei would leave his role when his contract expires at the end of the year and become an adviser. The company’s 83-year-old chairman, John Malone, will be the interim CEO. “While it’s never easy to leave an organization as dynamic as Liberty, I am confident that this is the right time,” Maffei, 64, said in a statement. He was a leading figure in the takeover of F1 in 2017 from long-time rights holder Bernie Ecclestone.