Add field for CF equivalent name

[mkavulich]

Description

This PR updates the XML, schema file, and Metadata files to include and "Equivalent CF name" field, to make it easier for code bases such as JEDI that need to interface with both CF standard names and ESM standard names.

In this process I also found and removed some duplicate names, and moved some names to better sections

Issues

Resolves #108

[climbfuji]

At first, I was confused of seeing cfname entires when they were identical to the ESM standard name, but I realized that this makes sense. Thanks for weeding through the CF names and adding the matches here.

[svahl991]

So let me confirm my understanding with this PR:

• Not every ESM name has an equivalent CF name
• Not every CF name has an equivalent ESM name
• Where there is an equivalence, it must be one-to-one

Is there code in place somewhere to enforce the last statement? Put another way, is there anything (other than human diligence) to prevent someone from accidentally pointing a new ESM name at a CF name that is already pointed to by another ESM name?