Should remove zeroth index from air_composition arrays

### Issue Type

Code Clean-up

### Issue Description

Currently some of the allocated arrays in `air_composition.F90` have a zero index where either N2 (if present) or average dry air values are set. While this does work and is "legal" Fortran, it doesn't match the general assumption that Fortran arrays always start at index one, and also with the philosophy that the atmospheric composition should be, as much as possible, set by the constituents provided by the chemistry and physics, instead of calculated internally in CAM-SIMA.

Given this, it would be good to modify the air_composition arrays and routines, and any routines that depend on them, to no longer need a zeroth index.

### Will this change answers?

No

### Will you be implementing this yourself?

Any Software Engineer can do this