Update kube-prometheus-stack chart to v35

- Automate kube-prometheus-stack helm release upgrades for the v35.x range
- Remove deprecated Grafana settings
- Set Prometheus retention to 24h
- Label Flux dashboards and PodMonitors with `app.kubernetes.io/component: monitoring`
- Change the `podMonitorSelector` to match the label `app.kubernetes.io/component: monitoring`

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

manifests/monitoring/monitoring-config/kustomization.yaml

@@ -6,8 +6,10 @@ resources:
 configMapGenerator:
   - name: flux-grafana-dashboards
     files:
-      - ../grafana/dashboards/control-plane.json
-      - ../grafana/dashboards/cluster.json
+      - dashboards/control-plane.json
+      - dashboards/cluster.json
     options:
       labels:
         grafana_dashboard: "1"
+        app.kubernetes.io/part-of: flux
+        app.kubernetes.io/component: monitoring