Resurrect the Atmospherics system

[cosmiccoincidence]

Summary

Bring the atmospheric system back from the dead.

We have a nice atmos system on our old 'outdated' branch and it needs to be ported over to our new game/branch.

Document

The original system can mostly be found in #367 and #374.

[cosmiccoincidence]

Nath has made some progress on this already but I wanted to add this here still to keep track of it.

[Ryan089]

Nath has made some progress on this already but I wanted to add this here still to keep track of it.

@cosmiccoincidence, should this task be assigned to @stilnat?

[stilnat]

One major issue with the old system is the inability to simulate depressurization, it currently acts more like the heat equation, I'm exploring other solutions based on particles that would also gives more flexibility on the number of gasses we can handle in the simulation.