Support for 301 redirects

[kirgene]

Is this a BUG or FEATURE REQUEST?:
FEATURE REQUEST
Did you review https://istio.io/help/ and existing issues to identify if this is already solved or being worked on?:
Y
Bug:
N

What Version of Istio and Kubernetes are you using, where did you get Istio from, Installation details

istioctl version git: 895d13c50a629bc69834448808d08a44b9de681c
kubectl version 1.10.2

Is Istio Auth enabled or not ?
Used generated file of the following command:
helm template install/kubernetes/helm/istio --name istio --namespace istio-system --set prometheus.enabled=true global.controlPlaneSecurityEnabled=true global.mtls.enabled=true sidecar-injector.enabled=true > istio-custom.yaml

What happened:
I'm trying to do HTTP 301 (permanent) redirect from Gateway via tls.httpsRedirect and VirtualService via redirect
What you expected to happen:

How to reproduce it:

Feature Request:
Y

Describe the feature:
Currently there is only 302 redirect type available. There should be an option for 301 redirect also.