Merge branch 'dev/master' of github.com:NOAA-GFDL/MOM6 into dev/master

Ulm release (21.0.0)

Ulm prerelease (21.0.0-beta)

Draft of SCM idealized hurricane wind forcing

- New initialization and forcing for a single column model
  with idealized hurricane wind forcing.

Draft of SCM idealized hurricane wind forcing

- New initialization and forcing for a single column model
  with idealized hurricane wind forcing.

Updated OMP directives for issue mom-ocean#78

- Added varaibles to shared(), private() OMP directives
  so that model compiles with OPENMP=1 on command-line.
- I have not run with openmp, only compiled.
- No answer changes (with non-openmp executable).
- Closes mom-ocean#78.

Last version before splitting repository

- About to move tools/ and examples/ to CommerceGov/NOAA-GFDL-MOM6-examples.

Answer changing:

- Turned on MLE parameterization in OM4_025.
- Re-write of MEKE.
- Fix underflow in conservation test in remapping_core().

Significant non-answer changing:
- Switch most analysis to ocean_annual_z output.
- Verified end-to-end preprocessing for OM4_025.
- CMORization of some diagnostics.

Missed a necessary fix for openmp (cf PR mom-ocean#68)

First candidate for Ulm city release