Draft//WIP Complete CCPPization of gravity wave drag (CAM4/5, CAM7?)

[jimmielin]

Holding as draft until HB is closed out and GW atmos_phys PR makes it through the first round of reviews. Opening draft PR to see pretty-printed diff.

todo: fill out changelog below

Tag name (required for release branches):
Originator(s):

Description (include the issue title, and the keyword ['closes', 'fixes', 'resolves'] followed by the issue number):

Describe any changes made to build system:

Describe any changes made to the namelist:

List any changes to the defaults for the input datasets (e.g. boundary datasets):

List all files eliminated and why:

List all files added and what they do:

List all existing files that have been modified, and describe the changes:
(Helpful git command: git diff --name-status development...<your_branch_name>)

If there are new failures (compared to the test/existing-test-failures.txt file),
have them OK'd by the gatekeeper, note them here, and add them to the file.
If there are baseline differences, include the test and the reason for the
diff. What is the nature of the change? Roundoff?

derecho/intel/aux_sima:

derecho/gnu/aux_sima:

If this changes climate describe any run(s) done to evaluate the new
climate in enough detail that it(they) could be reproduced:

CAM-SIMA date used for the baseline comparison tests if different than latest: