Add the same minimum round requirement security has to nukeops

[AmazingDragons]

I'm in favor of a round requirement for nukies, and honestly for revheads too. 15 rounds is not a, "you must fully understand how to effectively robust people and the combat system." 15 rounds means you understand basic mechanics, and have enough of an idea about the game that you can decide whether or not you want to play nukie. If you're a traitor and you have no idea what you're doing, at worst, security will be a bit bored that shift. If you're a nukie and you have no idea what you're doing, the entire round is boring for everyone, as the nukies are defeatedly easily.