Update EKS cluster docs and help links to clarify IAM role requirements

app/assets/javascripts/create_cluster/eks_cluster/components/eks_cluster_configuration_form.vue

@@ -153,7 +153,7 @@ export default {
         ),
         {
           startLink:
-            '<a href="https://docs.aws.amazon.com/eks/latest/userguide/getting-started-console.html#role-create" target="_blank" rel="noopener noreferrer">',
+            '<a href="https://docs.aws.amazon.com/eks/latest/userguide/service_IAM_role.html#create-service-role" target="_blank" rel="noopener noreferrer">',
           externalLinkIcon: this.externalLinkIcon,
           endLink: '</a>',
         },

doc/user/project/clusters/add_remove_clusters.md

@@ -331,8 +331,9 @@ new Kubernetes cluster to your project:
    - **Kubernetes cluster name** - The name you wish to give the cluster.
    - **Environment scope** - The [associated environment](index.md#setting-the-environment-scope-premium) to this cluster.
    - **Kubernetes version** - The Kubernetes version to use. Currently the only version supported is 1.14.
-   - **Role name** - Select the [IAM role](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles.html)
-     to allow Amazon EKS and the Kubernetes control plane to manage AWS resources on your behalf.
+   - **Role name** - Select the [IAM role](https://docs.aws.amazon.com/eks/latest/userguide/service_IAM_role.html)
+     to allow Amazon EKS and the Kubernetes control plane to manage AWS resources on your behalf. This IAM role is separate
+     to the IAM role created above, you will need to create it if it does not yet exist.
    - **Region** - The [region](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-regions-availability-zones.html)
      in which the cluster will be created.
    - **Key pair name** - Select the [key pair](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-key-pairs.html)