Output PUMAS variables on trop_cld_lev when possible

### What is the feature/what would you like to discuss?

Many PUMAS variables only have values in the lower atmosphere, as specified by `trop_cld_lev`. However, many variables also still seem to be output on the full range of model levels. This could result in CAM history files being larger than they actually need to be, which results in wasted disk space.

Given this, it might be good to go through the PUMAS/CAM interface and make sure that the variables that are output on the full number of model levels do so because they have to (e.g. they are pbuf variables), and otherwise to output them using the `trop_cld_lev` coordinate.

### Is there anyone in particular you want to be part of this conversation?

@cacraigucar @katc

### Will this change (regression test) answers?

I Don't Know

### Will you be implementing this enhancement yourself?

Any CAM SE can do this