add prometheus cluster health monitoring empty state

app/assets/javascripts/clusters/components/applications.vue

@@ -117,7 +117,10 @@
 </script>
 
 <template>
-  <section class="settings no-animate expanded">
+  <section
+    id="cluster-applications"
+    class="settings no-animate expanded"
+  >
     <div class="settings-header">
       <h4>
         {{ s__('ClusterIntegration|Applications') }}

app/views/projects/clusters/_health.html.haml

+
+%section.settings.no-animate.expanded#cluster-health
+  %h4= s_('ClusterIntegration|Kubernetes cluster health')
+
+  .settings-content
+    %p= s_("ClusterIntegration|In order to show the health of the cluster, we'll need to provision your cluster with Prometheus to collect the required data.")
+
+    %a.btn{ href: '#cluster-applications' }
+      = s_('ClusterIntegration|Install Prometheus')

app/views/projects/clusters/show.html.haml

@@ -22,6 +22,8 @@
   .js-cluster-application-notice
     .flash-container
 
+  = render 'health'
+
   %section.settings.no-animate.expanded#cluster-integration
     = render 'banner'
     = render 'integration_form'