Small atmos-related fixes

-the number of active turfs on the status tab will be refreshed and the end of each tick and when the air controller setup finishes.
-mining rooms will be generated before the air controller is created
-changed the total of moles of the NO2 turfs from 2000 to 6000 to compensate the replacement of the canister that spawns like 36000 moles on top of it for a normal canister. I'm talking about the NO2 canister inside of the chamber in atmos. (I will replace the canister in another pull request)