[DISCO-2967] deleting records error + CLI flag

[bendk]

References

JIRA: DISCO-2967

Description

Added the --allow-delete flag. If it's not present, don't allow records to be deleted. See https://bugzilla.mozilla.org/show_bug.cgi?id=1908802 for details. I turned off the flag for relevancy updates, because the bug only affects Suggest.

Refactored the CSV uploader so that it records changes it's going to make and executes them at the end. This is needed to correctly determine if there's a deletion. The current pattern is to delete all records, then update ones from the CSV data -- undoing the delete.

PR Review Checklist

Put an x in the boxes that apply

• [ ] This PR conforms to the Contribution Guidelines
• [ ] The PR title starts with the JIRA issue reference, format [DISCO-####], and has the same title (if applicable)
• [ ] [load test: (abort|warn)] keywords are applied (if applicable)
• [ ] Documentation has been updated (if applicable)
• [ ] Functional and performance test coverage has been expanded and maintained (if applicable)

[bendk]

This also affects other CSV uploaders, like MDN and pocket. I think that's correct, please tell me if I shouldn't be messing with them.

Does AMP use our uploader to update their data?