Deprecate unused grids?

[dougiesquire]

There are a lot of grids in this package and I suspect many of them are no longer used. A quick search across the COSIMA org suggests these are used:

access-om2/tools/make_cice_grid.py

• esmgrids.mom_grid.MomGrid
• esmgrids.cice_grid.CiceGrid

access-om2/tools/make_remap_weights.py

• esmgrids.mom_grid.MomGrid
• esmgrids.core2_grid.Core2Grid
• esmgrids.jra55_grid.Jra55Grid
• esmgrids.jra55_river_grid.Jra55RiverGrid
• esmgrids.daitren_runoff_grid.DaitrenRunoffGrid

access-om2/tools/make_salt_sfc_restore.py

• esmgrids.mom_grid.MomGrid
• esmgrids.woa_grid.WoaGrid

To make this package easier to quality-check, test and develop into the future, we could deprecate unused grids.

Proposal:

• Once we have a proper release process issue a release with warnings added to all unused grids saying that the grid will be deprecated in a subsequent release
• Deprecate the unused grids, but retain the code so that it can be resurrected (with proper testing) in the future

[anton-seaice]

The ERA5 grids are / were probably used recently by Ryan for the ERA5 driven OM2 runs.