Upgrade to babel 7 for v1 (#995)

* Upgrade babel 7
Use custom transform for jest to handle docs test since there is
path change in there

* change all version of babel dependency

* - add silent to yarn build
- add babel/types to expose  method used in translate-plugin

v1/lib/__tests__/build-files.test.js

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
-
+require('@babel/polyfill');
 const filepath = require('filepath');
 const fm = require('front-matter');
 const fs = require('fs-extra');