Add prometheus service discovery annotations

• This will enable prometheus to discover and scrape metrics from an auto-devops deployed application's /metrics endpoint.

• Adds service annotations of prometheus.io/scrape: and prometheus.io/port: to the auto-devops application

• Via helm install/upgrade use --set prometheus.metrics="true" to set the helm variable prometheus.metrics

• Also, protect the /metrics endpoint (via Ingress) from external access. Can still be accessed via the cluster prometheus

Related MRs

auto-deploy-image - gitlab-org/cluster-integration/auto-deploy-image!29 (closed)

gitlab (documentation) - gitlab-org/gitlab!18893 (closed)