Generate WB Grafana admin secret

clusters/wb/infrastructure/patches/prometheus-stack.yaml

@@ -26,7 +26,25 @@ spec:
       enabled: true
       adminUser: grafana-admin
       admin:
-        existingSecret: ""
+        existingSecret: grafana-admin
+        userKey: admin-user
+        passwordKey: admin-password
+      extraObjects:
+        - |
+          {{- $secret := lookup "v1" "Secret" .Release.Namespace "grafana-admin" }}
+          apiVersion: v1
+          kind: Secret
+          metadata:
+            name: grafana-admin
+            namespace: {{ .Release.Namespace }}
+            labels:
+              app.kubernetes.io/name: grafana
+              app.kubernetes.io/instance: {{ .Release.Name }}
+              app.kubernetes.io/managed-by: Helm
+          type: Opaque
+          data:
+            admin-user: {{ .Values.adminUser | b64enc | quote }}
+            admin-password: {{ if $secret }}{{ index $secret.data "admin-password" | quote }}{{ else }}{{ randAlphaNum 40 | b64enc | quote }}{{ end }}
       persistence:
         enabled: true
         type: sts