[Feature] Improvement in OPA polcies (request and response handling)

- Add function in OPA to retrieve request payload on-demand (Optmization)
- Rework input and ouput object structures for OPA
- Add support for adding status and headers in http response


>If you want this feature to be implemented, give it a thumbs up reaction, so that we can determine which features are important to you.
>👍
