[File system] Add `AssumeRoleWithWebIdentity` STS functionality for temporary credentials to S3 file system to support MinIO

[michaelkoepf]

Search before asking

• I searched in the issues and found nothing similar.

Motivation

The Fluss S3 file system currently only supports obtaining temporary credentials via session tokens. However, this STS endpoint is not supported by other S3-compatible object stores, e.g., MinIO. Using AssumeRoleWithWebIdentity allows Fluss users to use MinIO instead of AWS S3.

Solution

TBD

Anything else?

• AssumeRoleWithWebIdentity is currently the only endpoint that is supported by both MinIO and AWS S3
• This issue is blocked by [File system] Allow users to configure STS endpoint for S3 file system #613

Willingness to contribute

• I'm willing to submit a PR!