Add HPA to Istio Gateway deployments #152
Description
Summary
The Istio implementation of gateway API only creates a Deployment and a Service - no HorizontsalPodAutoscaler is created.
Motivation
A HPA is needed to provide scaling of Istion gateways. Scaling thresholds as well as minimum/maximum number of replicas could/should be configurable through the attached policies.
Proposal
Check if there is any progress on this from Istio, alternatively add a HPA resource template to blueprint.