Remove add item buttons when there are no permissions

src/frontend/js/app/nginx/proxy/main.ejs

@@ -3,7 +3,9 @@
     <div class="card-header">
         <h3 class="card-title">Proxy Hosts</h3>
         <div class="card-options">
+            <% if (showAddButton) { %>
             <a href="#" class="btn btn-outline-success btn-sm ml-2 add-item">Add Proxy Host</a>
+            <% } %>
         </div>
     </div>
     <div class="card-body no-padding min-100">