public DeploymentMetricsResponse getMetrics(Application application) {
        var hosts = getHostsOfApplication(application);
        var clusterMetrics = metricsRetriever.requestMetricsGroupedByCluster(hosts);
        return new DeploymentMetricsResponse(application.getId(), clusterMetrics);
    }
Finds all hosts we want to fetch metrics for, generates the appropriate URIs
and returns the generated MetricsResponse.

@author olaa
configserver/src/main/java/com/yahoo/vespa/config/server/metrics/DeploymentMetricsRetriever.java