Implements object versioning capabilities (v0.15.0) including:
- Bucket APIs: PutBucketVersioning, GetBucketVersioning
- Object Listing: ListVersions (lists versions and delete markers)
- Object Operations: Updated FileDownload, FileDelete, and FileDetails to support VersionId
- Integration tests covering the full versioning workflow (enable, upload versions, list, download specific version, delete specific version)
Documentation updated in README.md and ROADMAP.md.
"I have implemented Object Versioning (v0.15.0) as per the roadmap."
