Ahodges/documentation/doc158

@WatsonEmily please share with PMs who have worked through this process with data czars before... I'd love to get their feedback on level of detail and completeness.
@rocha and @stroilova , please let me know if this information is accurate (or designate others in Analytics).
@mhoeber and @srpearce , your feedback always welcome.

> the credentials.csv.gpg file, the result
> "When you open the credentials.csv file, you can see" -or- "The credentials.csv contains" (since the file contains this information whether or not the user opens the file)