Add missing by node aggregation (kube-burner#468)

## Type of change

- [ ] Refactor
- [ ] New feature
- [x] Bug fix
- [ ] Optimization
- [ ] Documentation Update

## Description

<!--- Describe your changes in detail -->

## Related Tickets & Documents

- Related Issue #
- Closes #

## Checklist before requesting a review

- [x] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.

Signed-off-by: Raul Sevilla <[email protected]>

cmd/kube-burner/ocp-config/metrics-aggregated.yml

@@ -128,7 +128,7 @@
   metricName: replicaSetCount
   instant: true
 
-- query: count(kube_pod_info{} AND ON (pod) kube_pod_status_phase{phase="Running"}==1)
+- query: count(kube_pod_info{} AND ON (pod) kube_pod_status_phase{phase="Running"}==1) by (node)
   metricName: podDistribution
 
 # Prometheus metrics

cmd/kube-burner/ocp-config/metrics.yml

@@ -119,7 +119,7 @@
   metricName: replicaSetCount
   instant: true
 
-- query: count(kube_pod_info{} AND ON (pod) kube_pod_status_phase{phase="Running"}==1)
+- query: count(kube_pod_info{} AND ON (pod) kube_pod_status_phase{phase="Running"}==1) by (node)
   metricName: podDistribution
 
 # Prometheus metrics