Add the same minimum round requirement security has to nukeops

[GORE]

During my early rounds I enjoyed rolling antag and experimenting with the systems more freely with less restrictions to the lethal impact of others.
Learning by making mistakes is the most profitrable option for likely a few people.

I would have been bummed out greatly by not even getting to make the decision whether I want to roll antag early on or not.

Let folks decide for themselves.