Parametrize delete operations and timeout for webhook in helm chart

The readme mentions how to [enable delete operations](https://github.com/open-policy-agent/gatekeeper\#enable-delete-operations) by saying you should modify the yaml for the ValidatingWebhookConfiguration. However, there is no way to do this in the helm chart withough using your own fork.
This fix allows to overwrite the value if you use the helm chart as a dependency.

Additionally the webhook timeout was parametrized because in our organization we actually have a few clusters with slower response times.

Both changes are not breaking any existing integrations, they just allow to overwrite default values

README.md

@@ -475,6 +475,8 @@ Note: For admission webhooks registered for DELETE operations, use Kubernetes v1
     - DELETE
 ```
 
+If you use the helm chart, set `enableDeleteOperations=true`.
+
 You can now check for deletes.
 
 #### Viewing the Request Object

charts/gatekeeper/templates/gatekeeper-validating-webhook-configuration-validatingwebhookconfiguration.yaml

@@ -31,10 +31,13 @@ webhooks:
     operations:
     - CREATE
     - UPDATE
+    {{- if .Values.enableDeleteOperations }}
+    - DELETE
+    {{- end}}
     resources:
     - '*'
   sideEffects: None
-  timeoutSeconds: 3
+  timeoutSeconds: {{ .Values.validatingWebhookTimeoutSeconds }}
 - clientConfig:
     caBundle: Cg==
     service:
@@ -51,8 +54,11 @@ webhooks:
     operations:
     - CREATE
     - UPDATE
+    {{- if .Values.enableDeleteOperations }}
+    - DELETE
+    {{- end}}
     resources:
     - namespaces
   sideEffects: None
-  timeoutSeconds: 3
+  timeoutSeconds: {{ .Values.validatingWebhookTimeoutSeconds }}
 {{- end }}

charts/gatekeeper/values.yaml

@@ -3,6 +3,8 @@ auditInterval: 60
 constraintViolationsLimit: 20
 auditFromCache: false
 disableValidatingWebhook: false
+validatingWebhookTimeoutSeconds: 3
+enableDeleteOperations: false
 auditChunkSize: 0
 logLevel: INFO
 emitAdmissionEvents: false