Incorporate MPAS-A OpenACC changes and Perlmutter for v2.1 release

[gdicker1]

This should be free to clone and test with. I'm looking to merge this in a few minutes so I can create the release branches/tags

Fixes #27

[gdicker1]

Relevant PRs in Externals:

• ccs_configs:
  • https://github.com/EarthWorksOrg/ccs_config_cesm/pull/13
  • https://github.com/EarthWorksOrg/ccs_config_cesm/pull/14
  • https://github.com/EarthWorksOrg/ccs_config_cesm/pull/15
• https://github.com/EarthWorksOrg/mpas-framework/pull/4
• https://github.com/EarthWorksOrg/CAM/pull/13
  • https://github.com/EarthWorksOrg/MPAS-Model/pull/1