V8: Allow nested content without blueprints (#4777)

* Don't assume there is at least one NC blueprint
* NC disabled icon styling (hover pointer type)
* Allow and handle NC configs without blueprints

src/Umbraco.Web.UI.Client/src/less/components/umb-nested-content.less

@@ -127,6 +127,9 @@
     border-radius: 200px;
     text-decoration: none !important;
 }
+.umb-nested-content__icon.umb-nested-content__icon--disabled:hover {
+    cursor: default;
+}
 
 .umb-nested-content__icon:hover,
 .umb-nested-content__icon--active

src/Umbraco.Web.UI.Client/src/views/propertyeditors/nestedcontent/nestedcontent.doctypepicker.html

@@ -34,7 +34,7 @@
                         <input type="text" ng-model="config.nameTemplate" />
                     </td>
                     <td>
-                        <a class="btn btn-danger" ng-click="remove($index)" ng-show="model.value.length > 1">
+                        <a class="btn btn-danger" ng-click="remove($index)">
                             <localize key="general_delete">Delete</localize>
                         </a>
                     </td>

src/Umbraco.Web.UI.Client/src/views/propertyeditors/nestedcontent/nestedcontent.html

@@ -37,7 +37,7 @@
         </div>
 
         <div class="umb-nested-content__footer-bar" ng-hide="nodes.length >= maxItems">
-            <a href class="umb-nested-content__icon" ng-click="openNodeTypePicker($event)" prevent-default>
+            <a href class="umb-nested-content__icon" ng-class="{ 'umb-nested-content__icon--disabled': !scaffolds.length }" ng-click="openNodeTypePicker($event)" prevent-default>
                 <i class="icon icon-add"></i>
             </a>
         </div>