Papa John International Inc.'s board of directors just got bigger — a lot bigger, in one way. The Louisville, Kentucky-based pizza giant announced Friday that NBA legend and ubiquitous pitchman Shaquille O'Neal has joined its board of directors. He's also an investor in nine Papa John’s restaurants in the Atlanta area and will enter into a marketing agreement to be an ambassador for the company's brand, according to a news release. Steve Ritchie, president and CEO of Papa John’s (Nasdaq:…