In a town where the most wanted stars and hardest-to-get tables shift from week to week, there has long been one steadfast epicenter of cool: the Chateau Marmont. Nestled high in the West Hollywood hills along L.A.’s famed Sunset Boulevard, it’s hotel to some, home to a few (Greta Garbo, Howard Hughes and Humphrey Bogart have been among the residents), clubhouse to others. There’s an eclectic mix of fashion folk, celebrities, artists and musicians who gather there on any given night — no…