Skip upload of CSV files that have already been uploaded

[nya-elimu]

If a CSV file has already been successfully uploaded, do not include that file in future uploads. Mark a CSV file as successfully uploaded if the server response is successful (HTTP 200...300): https://github.com/elimu-ai/webapp/tree/main/src/main/java/ai/elimu/rest/v2/analytics

This will reduce number of requests sent to the server.

Implement this in a way that does not exclude events that are added to an uploaded CSV file later the same day.

Also consider if this should be solved by updating the events stored in the database itself.

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• Depends on Include versionCode in CSV filename #116
• Depends on Do not return an error response when an event has already been uploaded webapp#1551
• Relates to Only upload datasets for the current version code #286
• Relates to Delete CSV files exported by previous versions of the app #300