Complete CCPPization of CAM7 hb_free_atm (for CAM-SIMA)

[jimmielin]

Tag name (The PR title should also include the tag name):
Originator(s): @jimmielin

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

• Complete CCPPization of CAM7 hb_free_atm for use above CLUBB

List all namelist files that were added or changed:

List all files eliminated and why:

List all files added and what they do:

A       test/test_suites/suite_vdiff_holtslag_boville_free_atm.xml
  - new SDF

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

M       schemes/vertical_diffusion/diffusion_stubs.F90
  - new Beljaars-only interstitial to facilitate reading from snapshot

List all automated tests that failed, as well as an explanation for why they weren't fixed:

Is this an answer-changing PR? If so, is it a new physics package, algorithm change, tuning change, etc?

New physics. Will be acc by CAM-SIMA PR to add regression test
Code is already in CAM from previous HB refactor and b4b

If yes to the above question, describe how this code was validated with the new/modified features: