example service monitoring updated with missing config

added service account, role and role binding for the prometheus frontend
example, also updated prometheus to use the correct service account

fixes #1049

manifests/examples/example-app/prometheus-frontend-role-binding.yaml

@@ -0,0 +1,13 @@
+apiVersion: rbac.authorization.k8s.io/v1beta1
+kind: RoleBinding
+metadata:
+  name: prometheus-frontend
+  namespace: default
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: prometheus-frontend
+subjects:
+- kind: ServiceAccount
+  name: prometheus-frontend
+  namespace: default