By Andrew Holleran If Colin Kaepernick ends up on an NFL roster for training camp, it looks like the Las Vegas Raiders are the favorite to make it happen. This week, Raiders owner Mark Davis showed public support for the free agent quarterback. That’s a pretty big step for Kaepernick, who hasn’t played in the National Football League in five years. A signing is probably still unlikely, but at least one NFL owner is showing public support for the dual-threat quarterback. “I believe in Colin Kaepernick,” Davis said, per Monte Poole of NBC Sports Bay Area. “He deserves every chance in the world t…