[MERGED PR] Adds the Security Assistant job

[Flaborized]

I like it, seems Good To Me! I don't know how easy to implement it would be, but having the sec assistant count as More Rounds towards the sec officer roundlock could be good? I'm also curious to see if two slots is too few, though I think we'll only really be able to tell through playtesting and seeing how players react to the role, and if it feels like an 'always full' sorta job.