Support k8s Gateway API

Work related to supporting k8s gateway api as an optional ingress provider for OpenShift.  Because the gateway api is a cluster scoped feature, there may be changes required to allow OpenShift Service Mesh to be installed as a singleton (i.e. cluster scoped install).  It may also be necessary to limit the feature set provided to only that supporting k8s gateway api and k8s ingress api (i.e. separating mesh features from gateway/ingress features).

Please also see relevant initiative doc: Gateway API support in OSSM

Sample code in OSSM 2.2 release notes

https://docs.openshift.com/container-platform/4.11/service_mesh/v2x/servicemesh-release-notes.html#new-features-red-hat-openshift-service-mesh-2-2
Kubernetes Gateway API is a technology preview feature that is disabled by default.
To enable the feature, set the following environment variables for the Istiod container in ServiceMeshControlPlane:

spec:
  runtime:
    components:
      pilot:
        container:
          env:
            PILOT_ENABLE_GATEWAY_API: true
            PILOT_ENABLE_GATEWAY_API_STATUS: true
            # and optionally, for the deployment controller
            PILOT_ENABLE_GATEWAY_API_DEPLOYMENT_CONTROLLER: true