add ww3 ice wave coupling

[mvertens]

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please refer to: https://github.com/CICE-Consortium/About-Us/wiki/Resource-Index#information-for-developers

PR checklist

• Short (1 sentence) summary of your PR:
  This PR adds ww3 coupling - I am not sure this is totally activated yet on the CICE side.
  It needs to also have accompanying CMEPS and WWDEV (dev/unified) PRs.

• Developer(s): mvertens

• Suggest PR reviewers from list in the column to the right.

• Please copy the PR test results link or provide a summary of testing completed below.
  To get the code - you need to do the following: (this has all of the updates in the Externals.cfg file)

> git clone https://github.com/mvertens/cesm
> cd cesm
> git checkout feature/add_icewave_coupling
> ./manage_externals/checkout_externals -v -o

I ran the following test - but wasn't sure how I could turn on the wave input in the cice6 code base

> cd cime/scripts
> ./create_test SMS.TL319_t061_wt061.GMOM_JRA_WD.cheyenne_intel

• How much do the PR code changes differ from the unmodified code?

  • bit for bit (unless wave coupling is turned on)
  • different at roundoff level
  • more substantial

• Does this PR create or have dependencies on Icepack or any other models?

  • Yes
  • No

• Does this PR add any new test cases?

  • Yes
  • No

• Is the documentation being updated? ("Documentation" includes information on the wiki or in the .rst files from doc/source/, which are used to create the online technical docs at https://readthedocs.org/projects/cice-consortium-cice/. A test build of the technical docs will be performed as part of the PR testing.)

  • Yes
  • No, does the documentation need to be updated at a later time? Yes
    • Yes
    • No

• Please provide any additional information or relevant details below: