Configure monitoring for bundled Envoy Gateway
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## Summary
GitLab chart now bundles a [Envoy Gateway](https://docs.gitlab.com/charts/charts/envoygateway/) instance as an alternative for (NGINX) Ingress.
## Acceptance Criteria
- [ ] Collaborated with Dedicated and .com infra to identify reusable monitoring configuration and manifests for Envoy Gateway that can be managed by GitLab chart
- [ ] monitoring configuration and manifests managed by GitLab chart (or follow-up created)
issue