Persist error logs in S3

[xmedr]

From a comment on pr #12:

We should give some thought as to how we can persist these logs on S3. Without that, if there's an issue or error with the translations for a particular event/document, it'll be basically impossible to quickly view the logs.

This is a really useful idea! Can consider logging warnings and errors with something like this: https://stackoverflow.com/a/78472888