[ESIP-CF] CodeLists definitions

[ted Habermann]

Nan et al.,

The official definitions for the ISO codeLists are at 
https://geo-ide.noaa.gov/wiki/index.php?title=ISO_19115_and_19115-2_CodeList_Dictionaries

Many of these are created in multi-lingual committees. Not a great spot for clarity or precision. There is also significant overlap between terms for various reasons.

Generally better to create a community agreed on usage...

Ted