* recommit #1590 to release-0.8
With the following changes:
1. Title: Securing Gateways with HTTPS
2. Added a step for redeploying istio-ingressgateway in Istio-0.8.0
1. For Istio 0.8.0, redeploy `istio-ingressgateway` with a volume to contain the
[CA](https://en.wikipedia.org/wiki/Certificate_authority) certificate that the server will use to verify its clients.
```command
$ kubectl apply -f <(helm template install/kubernetes/helm/istio --name istio --namespace istio-system -x charts/ingressgateway/templates/deployment.yaml --set ingressgateway.deployment.secretVolumes[0].name=ingressgateway-certs,ingressgateway.deployment.secretVolumes[0].secretName=istio-ingressgateway-certs,ingressgateway.deployment.secretVolumes[0].mountPath=/etc/istio/ingressgateway-certs,ingressgateway.deployment.secretVolumes[1].name=ingressgateway-ca-certs,ingressgateway.deployment.secretVolumes[1].secretName=istio-ingressgateway-ca-certs,ingressgateway.deployment.secretVolumes[1].mountPath=/etc/istio/ingressgateway-ca-certs)
deployment "istio-ingressgateway" configured
```
1. Create a Kubernetes `Secret` to hold the [CA](https://en.wikipedia.org/wiki/Certificate_authority) certificate,
namely `istio-ingressgateway-ca-certs` in namespace `istio-system`. The Istio gateway will automatically load the secret.
* add LibreSSL and macOS to .spelling
* rephrase the reference to the ingress task
* remove redundant trailing space
* fix the ingress links and the ingress port in endpoints guide
* fix a link to VirtualService gateways
* update links in FAQ about secure ingress
Vadim Eisenberg
Martin Taillefer
mtail