proxy: upload consumption events to S3

[khanova]

Problem

If vector is unavailable, we are missing consumption events.

https://github.com/neondatabase/cloud/issues/9826

Summary of changes

Added integration with the consumption bucket.

Works in xenon preview, example of events: https://s3.console.aws.amazon.com/s3/buckets/neon-dev-consumption-events-proxy?region=us-east-2&bucketType=general&tab=objects

Checklist before requesting a review

• I have performed a self-review of my code.
• If it is a core feature, I have added thorough tests.
• Do we need to implement analytics? if so did you add the relevant metrics to the dashboard?
• If this PR requires public announcement, mark it with /release-notes label and add several sentences in this section.

Checklist before merging

• Do not forget to reformat commit message to not include the above checklist

[github-actions]

2742 tests run: 2605 passed, 0 failed, 137 skipped (full report)

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Code coverage* (full report)

• functions: 28.2% (6348 of 22518 functions)
• lines: 47.0% (44603 of 94833 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
12a99a6 at 2024-03-28T17:30:44.471Z :recycle:}