fix: delete objects quiet mode, empty x-amz-object-attributes error code and optionally allow path traversal in object keys

[alanshaw]

• DeleteObjects controller parsed the request body into s3response.DeleteObjects — a struct that had no Quiet field — and then forwarded only Objects to the backend (types.Delete{Objects: dObj.Objects}). So input.Delete.Quiet was always nil → quiet=false.
• ErrObjectAttributesInvalidHeader error code was incorrect.
• Optionally allows path traversal in object keys - Ingot does not require but versitygw consumers with POSIX storage cannot support this.