Enable Istio sidecar injection

For testing with the Sail Operator and upstream Istio, the operand namespace
needs to be labeled, and the control-plane needs to be configured, to enable
sidecar injection in order to enable automated deployment.

* pkg/manifests/assets/router/namespace.yaml (metadata): Add label.
* pkg/operator/controller/gatewayclass/istio.go (desiredIstio): Enable sidecar
injection.

Author: Miciah

pkg/manifests/assets/router/namespace.yaml

@@ -6,6 +6,10 @@ metadata:
     openshift.io/node-selector: ""
     workload.openshift.io/allowed: "management"
   labels:
+    # The upstream Istio version that Sail Operator uses requires sidecar
+    # injection to be enabled on the namespace in order to enable automated
+    # deployment.
+    istio-injection: enabled
     # allow openshift-monitoring to look for ServiceMonitor objects in this namespace
     openshift.io/cluster-monitoring: "true"
     name: openshift-ingress

pkg/operator/controller/gatewayclass/istio.go

@@ -95,7 +95,7 @@ func desiredIstio(name types.NamespacedName, ownerRef metav1.OwnerReference) (*s
 					ExtraContainerArgs: []string{},
 				},
 				SidecarInjectorWebhook: &sailv1.SidecarInjectorConfig{
-					EnableNamespacesByDefault: ptr.To(false),
+					EnableNamespacesByDefault: ptr.To(true),
 				},
 				MeshConfig: &sailv1.MeshConfig{
 					AccessLogFile: ptr.To("/dev/stdout"),