Improve eslint rules (#3147)

* Add semi to ESLint rules

* Add padded-blocks to ESLint rules

* Add comma-dangle to ESLint rules

* add config/webpack and storyboard

* add streaming/

* yarn test:lint -- --fix

app/javascript/mastodon/features/account_timeline/components/header.js

@@ -21,7 +21,7 @@ class Header extends ImmutablePureComponent {
   };
 
   static contextTypes = {
-    router: PropTypes.object
+    router: PropTypes.object,
   };
 
   handleFollow = () => {