Enable coarse mesh resolution over the open ocean by using geojson file.

[andrewdnolan]

This pull request is a work in progress. It's purpose is to produce a coarse but variable resolution MALI mesh to be by used E3SM for testing / debugging purposes.

Checklist

• User's Guide has been updated
• Developer's Guide has been updated
• API documentation in the Developer's Guide (api.rst) has any new or modified class, method and/or functions listed
• Documentation has been built locally and changes look as expected
• The E3SM-Project submodule has been updated with relevant E3SM changes
• The MALI-Dev submodule has been updated with relevant MALI changes
• Document (in a comment titled Testing in this PR) any testing that was used to verify the changes
• New tests have been added to a test suite