new feature: services::Http should suport presign when authentication is not required

[NickCao]

Feature Description

Make services::Http support presign when connecting to public http servers.

Problem and Solution

The use case for presign is to grant access to certain resource without leaking the credentials. For public http servers, there are no credentials, therefore we can provide a trivial presign implementation by passing through the upstream server url, without weakening the security model.

Additional Context

This feature is useful in unit testing, for exercising the presign code path without having to setup a full minio or similar service.

Are you willing to contribute to the development of this feature?

• Yes, I am willing to contribute to the development of this feature.