Update dyn C/CD halo updates to mask and bundle fields

[apcraig]

PR checklist

• Short (1 sentence) summary of your PR:
  Update dyn C/CD halo updates to mask and bundle fields
• Developer(s):
  apcraig
• 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.
  full test suite run on cheyenne intel, pgi, gnu. Bit-for-bit. https://github.com/CICE-Consortium/Test-Results/wiki/cice_by_hash_forks#5927d0d6f820c022775bd16f65b699be33fb1917
• How much do the PR code changes differ from the unmodified code?
  • bit for bit
  • 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
    • No
• Please provide any additional information or relevant details below:

Update dyn C/CD halo updates to mask and bundle fields
Used 5 point stencil for C/CD halo mask (similar to current land block elimination for C/CD). This may still be improved. See CICE-Consortium#700
Rename stack_velocity_field to stack_fields and overload

[eclare108213]

Looks good. Will be interesting to see how much this changes computational performance.

[apcraig]

This seems to improve the dynamics time in the C/CD cases by about 10% for a sample test case. This gets us part of the way to matching B performance but still work to do.

[apcraig]

Reran full test suite, all good.