Add column for grid variables for CESM parsers

[mgrover1]

It would be helpful to have a list of grid variable names, such that one could easily create a dataset of only the grid variables, or append this to the single variable or variables to their search within a data catalog

[sherimickelson]

If you're pulling the grid data from an existing NetCDF file, could you just use the dimension/attributes/coordinate information that exists within the file to get the grid variable names? All of that information should exist since NetCDF is self describing. If it doesn't, maybe the file isn't compliant? Doing it this way could result in more flexible code that has less assumptions that could break later on.