Replace Ingress and RouteRule with Gateway and VirtualService respectively

[ZhiminXiang]

Since we already upgraded Istio to 0.8.0, it is better for us to replace Ingress and RouteRule with Gateway and VirtualService respectively to take advantage of new Istio features.

[hanshengchiu]

Hi, I was trying the gRPC go sample and couldn't get it working. Has this issue been resolved?

*I installed knative serving 0.2.2.

[ravindranathakila]

Hi, I was trying the gRPC go sample and couldn't get it working. Has this issue been resolved?

*I installed knative serving 0.2.2.

I'm having this problem @hanshengchiu. Did you encounter this boss? ;)