fix(s3exporter/config-validation): endpoint should contain region and S3 bucket

[dabcoder]

Description:

Discussion: #32766.

Link to tracking Issue: #32774

Testing: added test cases to validate config when endpoint is provided.

Documentation: updated README.

Configuration logic:

• An endpoint is provided, and Region still needs to be provided (as per the AWS SDK Go config, even though the region can be included in the endpoint itself). The S3 bucket name is optional.
• An endpoint is not provided, thus region and S3 bucket name should be provided (return an error for each if one of those 2 isn't)

Tasks:

• Add entry to changelog
• Edit the docs

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: dabcoder / name: David B. (b29567c, 853d916, acf7ce2, 3d95e5a, df9b2a0, c79f375, fa5ca3f, 1386794, e7c0a6a, 5a23120, 7b60ae7, b3f2f61, 362a623)

[dabcoder]

Actually I am not sure what protocol endpoint should use. I am seeing unsupported protocol scheme \"s3\""} errors in logs when using an endpoint starting with s3://, so we may also need to clarify that this support http(s) only?

[dabcoder]

cc @atoulme @pdelewski.

[atoulme]

Actually I am not sure what protocol endpoint should use. I am seeing unsupported protocol scheme \"s3\""} errors in logs when using an endpoint starting with s3://, so we may also need to clarify that this support http(s) only?

Yes, I guess so.

[dabcoder]

@bogdandrutu anything else I should do in order to merge this?

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[dabcoder]

@open-telemetry/collector-contrib-maintainer if anyone has a chance to take another look at this PR before it gets marked as stale again, that'd be great, thanks.

[dmitryax]

@dabcoder PTAL at the failing tests

[dabcoder]

Thanks @dmitryax. They should be fixed now, I ran the tests locally and they're passing.