Installing on Azure docs should be updated to indicate known issues and workarounds

[krancour]

Knative itself isn't implicated in these issues, but they should be noted so that they don't take users by surprise.

Known issue: Istio prevents controllers that use an istio-proxy sidecar from talking to the apiserver: istio/istio#8696
Effect: Autoscaling doesn't work
Workaround: Use istio-lean.yaml instead

Known issue: Deploying/scaling workloads and propagating network routes are all sluggish: Azure/AKS#620
Effect: Sluggish deployments will be evident to operators. Some requests may time out during / after scale up from zero.
Workaround: None at this time, but this behavior should be noted.

[krancour]

/assign krancour

[mattmoor]

Reopen on the docs repo if you still plan to pursue this?