Deprecate support/testing for NWP with Bgc/BgcCrop

[ekluzek]

The main usage for NWP in CTSM is with SP rather than BGC or BGC-Crop. Supporting both NWP with SP and BGC/BGC-Crop adds more options and complexity to our compsets and compset options as well as to our testing. Since, right now we don't envision there is a user base behind NWP with Bgc, we will deprecate it and start removing it as something that can be easily done and tested. Users could still run this way if desired by setting XML options, but it won't be available at the compset level, won't be tested, and users would be on their own if they find problems.

Definition of done:

• [ ] Mark it as deprecated in appropriate README files
• [ ] Mark it as deprecated in doc/IMPORTANT_NOTES
• [ ] Remove any NWP-Bgc tests
• [ ] Remove the option from config_compsets.xml
• [ ] Remove the capability in config_component.xml (in description)

What we could do:

• [ ] Mark it as a warning in build namelist (can be overridden by adding --ignore_warnings to CLM_BLDNML_OPTS)
• [ ] Above, but as a fatal error

[ekluzek]

In #640 we found problems in trying to run this way for the matrix code. This is one example of starting to deprecate this option.