Fix install CRD steps on various pages (#4680)

* Fix install CRD steps on various pages

* Fix ordering to create namespace first

content/docs/examples/multicluster/gke/index.md

@@ -112,9 +112,9 @@ the `default` namespace:
 
 {{< text bash >}}
 $ kubectl config use-context "gke_${proj}_${zone}_cluster-1"
-$ kubectl apply -f install/kubernetes/helm/istio-init/files/crd/
 $ helm template install/kubernetes/helm/istio --name istio --namespace istio-system > $HOME/istio_master.yaml
 $ kubectl create ns istio-system
+$ helm template install/kubernetes/helm/istio-init --name istio-init --namespace istio-system | kubectl apply -f -
 $ kubectl apply -f $HOME/istio_master.yaml
 $ kubectl label namespace default istio-injection=enabled
 {{< /text >}}

content/docs/setup/kubernetes/install/multicluster/gateways/index.md

@@ -99,11 +99,13 @@ Cross-cluster communication occurs over Istio gateways of the respective cluster
             --from-file=@samples/certs/cert-chain.pem@
         {{< /text >}}
 
-    * Install Istio's CRDs:
+    * Install all the Istio
+    [Custom Resource Definitions](https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/#customresourcedefinitions)
+    (CRDs) using `kubectl apply`, and wait a few seconds for the CRDs to be committed in the Kubernetes API-server:
 
-        {{< text bash >}}
-        $ kubectl apply -f install/kubernetes/helm/istio-init/files/crd/
-        {{< /text >}}
+    {{< text bash >}}
+    $ helm template install/kubernetes/helm/istio-init --name istio-init --namespace istio-system | kubectl apply -f -
+    {{< /text >}}
 
     * {{< boilerplate verify-crds >}}
 

content/docs/tasks/security/vault-ca/index.md

@@ -28,7 +28,7 @@ to Node Agent, which returns the signed certificate to the Istio proxy.
     {{< text bash >}}
     $ kubectl create clusterrolebinding cluster-admin-binding --clusterrole=cluster-admin --user="$(gcloud config get-value core/account)"
     $ kubectl create namespace istio-system
-    $ kubectl apply -f install/kubernetes/helm/istio-init/files/crd/
+    $ helm template install/kubernetes/helm/istio-init --name istio-init --namespace istio-system | kubectl apply -f -
     $ helm template \
         --name=istio \
         --namespace=istio-system \