build(aio): refactor dgeni packages

This is to tidy up the `author-packagse`, which currently duplicates a
lot of the configuration in the main packages. We need to
DRY this up so that we don't fall foul of a change in one being missed in
the other.

aio/tools/transforms/angular-api-package/processors/addNotYetDocumentedProperty.js

@@ -0,0 +1,37 @@
+module.exports = function addNotYetDocumentedProperty(EXPORT_DOC_TYPES, log, createDocMessage) {
+  return {
+    $runAfter: ['tags-parsed'],
+    $runBefore: ['rendering-docs'],
+    $process: function(docs) {
+      docs.forEach(function(doc) {
+
+        if (EXPORT_DOC_TYPES.indexOf(doc.docType) === -1) return;
+
+        // NotYetDocumented means that no top level comments and no member level comments
+        doc.notYetDocumented = notYetDocumented(doc);
+
+        if (doc.constructorDoc) {
+          doc.constructorDoc.notYetDocumented = notYetDocumented(doc.constructorDoc);
+          doc.notYetDocumented = doc.notYetDocumented && doc.constructorDoc.notYetDocumented;
+        }
+
+        if (doc.members) {
+          doc.members.forEach(function(member) {
+            member.notYetDocumented = notYetDocumented(member);
+            doc.notYetDocumented = doc.notYetDocumented && member.notYetDocumented;
+          });
+        }
+
+        if (doc.notYetDocumented) {
+          log.debug(createDocMessage('Not yet documented', doc));
+        }
+      });
+
+      return docs;
+    }
+  };
+};
+
+function notYetDocumented(doc) {
+  return !doc.noDescription && doc.description.trim().length == 0;
+}