Better support of multiple vertical coordinates

[mnlevy1981]

I think we should add MOM6_VERTICAL_COORD (or something similar) to env_run.xml that let's users choose between zstar and hybrid, and then ParamGen and MOM_input.yaml can get the parameters right for either. This will make it easier to run experiments comparing the two options.

Note that there might also need to be some work done to support the hybrid coordinate; when I make changes in user_nl_mom, I need ALE_COORDINATE_CONFIG to specify a file in my run directory. It should support pointing to a file in inputdata rather than requiring a copy into RUNDIR.

[gustavo-marques]

Solved via #158