By Jenny Peters This is Concierge Confidential, a series in which we learn about a city’s best-kept secrets from people who specialize the exactly that: long-serving concierges from the best hotels in town. The Langham Hotel Chicago has it all: The Forbes top five-star rating, a central city location, rooms with a view, an opulent top-floor club level, and chief concierge Philippe Gills, their Chicago Concierge Hall of Fame inductee and longtime member of Les Clefs d’Or USA, the international association of top concierges. We asked Gills to uncover the unique things that make the Windy City su…