Add helm chart repo to helm docs (#784)

Helm docs do not mention the chart repo, which will be useful for anyone who doesnt want to download the source code or is using argocd/terraform

Author: domenicbove

Diff for: docs/content/docs/operations/helm.md

@@ -26,13 +26,20 @@ under the License.
 
 # Helm installation
 
-The operator installation is managed by a helm chart. To install run:
+The operator installation is managed by a helm chart. To install with the chart bundled in the source code run:
 
 ```
 helm install flink-kubernetes-operator helm/flink-kubernetes-operator
 ```
 
-Alternatively to install the operator (and also the helm chart) to a specific namespace:
+To install from our Helm Chart Reporsitory run:
+
+```
+helm repo add flink-operator-repo https://downloads.apache.org/flink/flink-kubernetes-operator-<OPERATOR-VERSION>/
+helm install flink-kubernetes-operator flink-operator-repo/flink-kubernetes-operator
+```
+
+Alternatively to install the operator (and also the helm chart) to a specific namespace add the arguments `--namespace` and `--create-namespace` ex:
 
 ```
 helm install flink-kubernetes-operator helm/flink-kubernetes-operator --namespace flink --create-namespace