[MERGED PR] Makes security slots scale at lower population

[EmeraldCrow]

This feels a little tricky to me: I've been an sole antag with a full sec team, HoS, and NTSO, and I felt way to intimidated to act, which isnt fun for anyone. But I've also seen sole antags deal massive damage to the station where a big sec team is warranted. I like the idea of NTSO and HoS lowering future sec openings but not stopping them from joining.

An idea I had was that one could count the number of dead people in the round, and open up more sec slots if its high.