Firefighting changes

-Firesuit level protection is no longer invincible to being on fire. You very slowly gain temperature while on fire in a fire suit, etc. For comparison, someone who is not wearing fire suit level protection will burn all the way to death before someone in firesuit gear hits crit.

-Changes the Atmos water backpack into a significantly more robust tool.
1. Functions as 200 capacity water extinguisher that has a tile range of 8
2. If swapped to "Nanofrost" mode, lobs an object 5 tiles that detonates, chilling the temperature of any tile in a 3x3 radius to 2 degrees, and and tiles within a 5x5 radius that have active hotspots in them will have any remaining plasma and oxygen in that tile converted into nitrogen, and the hotspot extinguished. This ability has a 10 second cooldown and costs 100 water. This is for curbing down the length of the fire, and cooling down the air in the area after the fact.
3. Metal foam dispenser: Creates single tiles of metal foam (5, then a cooldown occurs). This is for barricading off a hull breach or if you can't gain access to an area in time, to seal off windows to contain the fire etc. Metal foam doesn't have click lag, so it's super easy to bust through.

Refills from existing water tanks. Activate in hand to swap modes.

-Adds a secure atmos closet that contains the Atmos water backpack and some other atmos-y gear, but doesn't place it on the map, since there's already a water backpack in the spacesuit container in atmos currently

While the new backpack is much more robust at fighting fires, it's not gonna singlehandedly save the station when the entire place is filled to the brim with plasma.
Make the nozzle_mode vars defines, and swap this if chain with a switch()