feat(ObjectStore): Make the S3 concurrency option configurable

[susnux]

• Closes: Make S3 MultipartUpload Concurrency Configurable - Address S3 Timeouts #24330

Summary

Based on this: #24330 (comment)

So this makes the concurrency option configurable which might help in some cases, but still defaults to 5 like the S3 SDK is doing.

Docs: nextcloud/documentation#11661

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[susnux]

No idea whats up with Cypress, but that is unrelated...

[come-nc]

@susnux https://github.com/nextcloud/server/actions/runs/8413780258/job/23036516249 Sorry I missed that, you cannot type sizes as int, it breaks on 32bits, you should use int|float.