refactor: remove k8s and use release name for instance

!8

templates/PrometheusRule-nodeExporter.yaml

@@ -4,11 +4,12 @@ kind: PrometheusRule
 metadata:
   labels:
     app.kubernetes.io/component: exporter
+    app.kubernetes.io/instance: {{ $.Release.Name }}
     app.kubernetes.io/name: node-exporter
     app.kubernetes.io/part-of: {{ $.Chart.Name }}
     app.kubernetes.io/version: {{ $.Chart.Version }}
     app.kubernetes.io/managed-by: {{ $.Release.Service }}
-    prometheus: k8s
+    prometheus: {{ $.Release.Name }}
     role: alert-rules
   name: node-exporter-rules
   namespace: {{ .Values.nfc_monitoring.prometheus.namespace }}