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-base-package/processors/convertToJson.js

@@ -0,0 +1,40 @@
+module.exports = function convertToJsonProcessor(log, createDocMessage) {
+
+  return {
+    $runAfter: ['checkUnbalancedBackTicks'],
+    $runBefore: ['writeFilesProcessor'],
+    docTypes: [],
+    $process: function(docs) {
+      const docTypes = this.docTypes;
+      docs.forEach((doc) => {
+        if (docTypes.indexOf(doc.docType) !== -1) {
+          let contents = doc.renderedContent || '';
+
+          let title = doc.title;
+
+          // We do allow an empty `title` but resort to `name` if it is not even defined
+          if (title === undefined) {
+            title = doc.name;
+          }
+
+          // If there is no title then try to extract it from the first h1 in the renderedContent
+          if (title === undefined) {
+            const match = /<h1[^>]*>(.+?)<\/h1>/.exec(contents);
+            if (match) {
+              title = match[1];
+            }
+          }
+
+          // If there is still no title then log a warning
+          if (title === undefined) {
+            title = '';
+            log.warn(createDocMessage('Title property expected', doc));
+          }
+
+          doc.renderedContent = JSON.stringify({ id: doc.path, title, contents }, null, 2);
+        }
+      });
+    }
+  };
+
+};