Update from cmip6 to cmip7 co2 stream file

[slevis-lmwg]

CDEPS issues:
Resolves #352
Resolves #361

Are there dependencies on other component PRs (if so list):
CTSM issue ESCOMP/CTSM#3386
CTSM PR to update .gitmodules with this PR's changes: TODO

Are changes expected to change answers (bfb, different to roundoff, more substantial):
Yes, more than roundoff, because the cmip7 co2 dataset differs from its cmip6 counterpart.

Any User Interface Changes (namelist or namelist defaults changes):
The new dataset spans 1750-2022 instead of 1750-2014.

Testing performed (e.g. aux_cdeps, CESM prealpha, etc):
So far, I completed 1-day simulations in

/glade/derecho/scratch/slevis/archive/IHistClm6BgcCropCrujra_f09_ctsm5.4.003/cmip7co2
/glade/derecho/scratch/slevis/archive/IHistClm6BgcCropCrujra_f09_ctsm5.4.005

and the PCO2 output looks

• identical in these two cmip7 cases and
• similar to the following cmip6 1-day baseline:
  /glade/derecho/scratch/slevis/archive/IHistClm6BgcCropCrujra_f09_ctsm5.4.003/cmip6co2

Hashes used for testing:
1-day baseline: ctsm5.4.003
1-day experiment: ctsm5.4.003 with co2 stream changes in user_nl_datm_streams
1-day experiment: ctsm5.4.005 with cdeps1.0.84-1-g5a06fe0 (this PR)

[slevis-lmwg]

I would like a preliminary review of this PR before I

• submit the aux_cdeps test-suite
• ./rimport and relink the new file

@ekluzek would you like to look at this or recommend another reviewer? Only 5 lines have changed.

[slevis-lmwg]

I suspect that we will rename the new file. I did not wish to do so until I had confirmation.

[ekluzek]

I think we should retain the old dataset, so we can more easily compare and make sure the new dataset is correct.

[ekluzek]

The new file does need a creation date on it.and it needs to say CMIP7.

And actually the dataset above has all the greenhouse gases on it. In the past we just lifted out CO2 for the CDEPS streams. That might be worth doing, so it's clear those other fields aren't used. But, it also allows them to be added in easier in the future in case there might be a scientific need for it.