Gateway API | Support HTTP -> HTTPS upgrade
## Summary
The current implementation of Ingress NGINX has a default behaviour of upgrading HTTP requests to HTTPS. The Envoy Gateway deployment in GitLab Charts does not currently do this by default.
To keep compatibility with the old implementation, I think it would make sense for this to be a default in Envoy Gateway.
This can be implemented through [an explicit RequestRedirect](https://gateway-api.sigs.k8s.io/guides/http-redirect-rewrite/?h=requestredirect#supported-status-codes).
## Acceptance Criteria
- [ ] HTTP requests are upgraded to HTTPs matching the nginx behaviour.
issue