Re-add gang and conspiracy to secret

[BaneOfGiygas]

Plus, in the context of these gangs being...gangs, it doesn't make a whoooole lot of sense for people to be able to join a gang without the gang leader's consent, or even possibly their knowledge, and some manner of regulating who is able to get into a gang should be in place. It would also help the balance issues that Frank_Stein went over: Plop your locker in Research and suddenly you have bombing teams that would make the syndies quake in their boots.