[release/v1] Add a new field for equivalent CF standard name?

[mkavulich]

Since we have decided to allow divergence from the original CF standard names, but there is still a large amount of overlap in both the names and the applications, should we attempt to introduce some inter-compatibility for the equivalent CF standard names? It seems like this could be useful down the road for applications that have or deal with a mix of the two naming conventions.

As an example of what I'm thinking, an optional xml entry "cf_name" could exist alongside "standard_name":

    <standard_name name="air_pressure_at_surface"
                   cf_name="surface_air_pressure" long_name="Air pressure at local surface">
      <type kind="kind_phys" units="Pa">real</type>

While there's no way to ensure that the association is correct aside from manual review, this field could be automatically checked against the current CF standard names table (https://cfconventions.org/Data/cf-standard-names/current/src/cf-standard-name-table.xml) to ensure the cf_name is valid.