Windows builds and testing

[kafitzgerald]

We don't currently have testing in place (as far as I can tell, we never did in CI) or releases for Windows builds of WRF-Python (we did have these on conda-forge at one point, but dropped them following the build system changes).

It'd be great to get this going again.

[akrherz]

c/f conda-forge/wrf-python-feedstock/issues/81