[PORT] Fixes things being statistically weighted to drop in security

[Absolucy]

About The Pull Request

Port of tgstation/tgstation#88788

Hey, fun fact, get_safe_random_station_turf() is not as random as it seems. The more areas a department has (blame security), there is a much bigger chance for it to land in that department.

Creates a get_safe_random_station_turf_equal_weight() which first picks a department, creates a list of areas from that department, to then pass into get_safe_random_station_turf()

Why It's Good For The Game

Here's get_safe_random_station_turf() ran 1000 times.

204 - Security
105 - Science
106 - Engineering
101 - Medical
61 - Cargo 
118 - Service
7 - Maintenance (This is only the xenobio cuck room, so it doesn't matter)
85 - Command
79 - Hallway
84 - AI Monitored (Vault, AI sat, etc)

As you can see, the probability for choosing a place like security is much higher. Yes, this is funny for things like the CRAB. But the probability for choosing anywhere else (like command) can be less then 10 percent.

Here's with this proc.

Security - 107
Science - 107
Engineering - 105
Hallway - 94
Command - 104
Medical - 109
Service - 106
Cargo - 105
AI_monitored - 127

Changelog

🆑 Absolucy, StrangeWeirdKitten
fix: Things that drop in random places are no longer statistically weighted to drop in security.
/:cl: