Add pole_kind to grids

[huard]

• Add docstring. Handle ESMF versions prior to 8.0.1 that do not support pole_kind option.

[raphaeldussin]

we should use #228 to generate a synthetic tripolar grid for the testing. I have a PR that fixes a minor testing issue that needs to go through first then we should get this one in.

[huard]

Salut @raphaeldussin

Is this something that can reasonably done over summer ?

[raphaeldussin]

Salut @huard

The code basically works, I've been working on a test with synthetic data from tripolar to regular lat/lon but I can't get it to generate different solutions with and without the option. I suspect the test is too simple... I'm going to work on this very soon because I really want this option to be available as it greatly improves remapped solution in the Arctic.