chart: update monitoring resources (#329)

### Monitoring settings:
* Disabled rendering of Prometheus resources by default.
* Added a new relabeling configuration to replace the `instance` label based on the `app_kubernetes_io_name` label. Instance will be displayed as Helm release name instead of pod IP address.

### Grafana dashboard configuration:
* Changed the `interval` field for several metrics queries from `"$__rate_interval"` to `"$interval"`.
* Updated the `refresh` interval from `30s` to `1m`.
* Added a new variable for `Step Interval` with default value `2m`.

### Chart version update:
* Updated the chart version from `0.4.0` to `0.5.0`.

Signed-off-by: Dmytro Bondar <git@bonddim.com>

deploy/helm/templates/monitoring.yaml

@@ -23,8 +23,13 @@ spec:
       {{- with .metricRelabelings }}
       metricRelabelings: {{- toYaml . | nindent 8 }}
       {{- end }}
+      relabelings:
+        - action: replace
+          sourceLabels:
+            - __meta_kubernetes_pod_label_app_kubernetes_io_name
+          targetLabel: instance
       {{- with .relabelings }}
-      relabelings: {{- toYaml . | nindent 8 }}
+      {{- toYaml . | nindent 8 }}
       {{- end }}
       {{- with .scrapeTimeout }}
       scrapeTimeout: {{ . }}