build(aio): move doc-gen stuff from angular.io (#14097)

tools/docs/angular.io-package/processors/generateNavigationDoc.js

@@ -0,0 +1,49 @@
+module.exports = function generateNavigationDoc() {
+
+  return {
+    $runAfter: ['extra-docs-added'],
+    $runBefore: ['rendering-docs'],
+    outputFolder: '',
+    $validate: {outputFolder: {presence: true}},
+    $process: function(docs) {
+      var modulesDoc = {
+        docType: 'data-module',
+        value: {api: {sections: []}, guide: {pages: []}},
+        path: this.outputFolder + '/navigation',
+        outputPath: this.outputFolder + '/navigation.ts',
+        serviceName: 'NAVIGATION'
+      };
+
+      docs.forEach(function(doc) {
+        if (doc.docType === 'module') {
+          var moduleNavItem =
+              {path: doc.path, partial: doc.outputPath, name: doc.id, type: 'module', pages: []};
+
+          modulesDoc.value.api.sections.push(moduleNavItem);
+
+          doc.exports.forEach(function(exportDoc) {
+            if (!exportDoc.internal) {
+              var exportNavItem = {
+                path: exportDoc.path,
+                partial: exportDoc.outputPath,
+                name: exportDoc.name,
+                type: exportDoc.docType
+              };
+              moduleNavItem.pages.push(exportNavItem);
+            }
+          });
+        }
+      });
+
+      docs.forEach(function(doc) {
+        if (doc.docType === 'guide') {
+          console.log('guide', doc.name);
+          var guideDoc = {path: doc.path, partial: doc.outputPath, name: doc.name, type: 'guide'};
+          modulesDoc.value.guide.pages.push(guideDoc);
+        }
+      });
+
+      docs.push(modulesDoc);
+    }
+  };
+};