Add action, knobs and docs add-ons

Author: andrewn

.storybook/main.js

@@ -1,6 +1,6 @@
 module.exports = {
-  stories: ['../stories/**/*.stories.js'],
-  addons: ['@storybook/addon-actions', '@storybook/addon-links'],
+  stories: ['../client/**/*.stories.(jsx|js|mdx)'],
+  addons: ['@storybook/addon-actions', '@storybook/addon-docs', '@storybook/addon-knobs', '@storybook/addon-links'],
   webpackFinal: async config => {
     // do mutation to the config