Palmer Luckey, photographed exclusively for the Telegraph Magazine at Facebook's headquarters in Menlo Park, California, December 2014. Credit: Photo: Carlos Chavarría A few months after his 21st birthday, Palmer Luckey signed a deal even Silicon Valley would gawp at. His fledgling start-up had just been bought for $2.3 billion by Facebook with a promise from the latter’s CEO, Mark Zuckerberg, tha