NewUnmanaged creates and returns a controller that watches gatewayclasses and installs and configures Istio.

OpenShiftDefaultGatewayClassName is the name of the default gatewayclass that Istio creates when it is installed.

OpenShiftGatewayClassControllerName is the string by which a gatewayclass identifies itself as belonging to OpenShift Istio.

Config holds all the configuration that must be provided when creating the controller.