Add prep_zap, fix CSV work

[pburkholder]

Changes proposed in this pull request:

-

• Add steps on how to use the CSV file
• Restore the prep_zap step
• Summarize what to do before the Summary File Process
• Renamed Google Drive Processing to "Summary File Processing"

security considerations

Safe. Nothing net new here, just clarifying steps

[pburkholder]

@Chiakao or @wz-gsa is this PR still potentially useful, or should I close it unmerged?