CLI: initial save/read paired dataset support for melodies-monet run

[zmoon]

1. if analysis.read is present in the config, read saved paired datasets instead of pairing
2. if analysis.save is present in the config, save paired datasets

This is something I've been using for a while, and it's been working fine.

[zmoon]

Maybe should have separate message for each case here, for clarity ("Reading saved paired datasets" vs "Pairing")

[zmoon]

Oh but I guess the file names are already printed when reading

[zmoon]

linkcheck failed for https://www3.epa.gov/ttn/naaqs/standards/ozone/data/20140131healthrea4a.pdf, which is indeed currently unreachable

In the idealized config CLI test run, getting permission denied for saving the file:

 Writing: ./output/idealized/asdf_test_obs_test_model.nc4
Saving paired datasets failed in 0.209 seconds
Error message: [Errno 13] Permission denied: '/home/runner/work/MELODIES-MONET/MELODIES-MONET/docs/examples/output/idealized/asdf_test_obs_test_model.nc4'

I guess this is because it has that file open, which was created when running the idealized example nb. So may have to create separate configs for writing/reading.

Update: fixed in b588ebe

[bbakernoaa]

@rschwant @colin-harkins can one of you take a look at this

[colin-harkins]

This looks good to me. Thanks for making a test for this.