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/ui/components/upload_area.js

@@ -8,14 +8,14 @@ class UploadArea extends React.PureComponent {
 
   static propTypes = {
     active: PropTypes.bool,
-    onClose: PropTypes.func
+    onClose: PropTypes.func,
   };
 
   handleKeyUp = (e) => {
     e.preventDefault();
     e.stopPropagation();
 
-    const keyCode = e.keyCode
+    const keyCode = e.keyCode;
     if (this.props.active) {
       switch(keyCode) {
       case 27: