template: Gather the prometheus target metadata during teardown

This will let us see the names of all metrics for a run and their
help info.

Author: smarterclayton

ci-operator/templates/openshift/installer/cluster-launch-installer-e2e.yaml

@@ -862,6 +862,7 @@ objects:
 
           echo "Snapshotting prometheus (may take 15s) ..."
           queue /tmp/artifacts/metrics/prometheus.tar.gz oc --insecure-skip-tls-verify exec -n openshift-monitoring prometheus-k8s-0 -- tar cvzf - -C /prometheus .
+          FILTER=gzip queue /tmp/artifacts/metrics/prometheus-target-metadata.json.gz oc --insecure-skip-tls-verify exec -n openshift-monitoring prometheus-k8s-0 -- /bin/bash -c "curl -G http://localhost:9090/api/v1/targets/metadata --data-urlencode 'match_target={instance!=\"\"}'"
 
           echo "Running must-gather..."
           mkdir -p /tmp/artifacts/must-gather