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/reducers/modal.js

@@ -3,7 +3,7 @@ import Immutable from 'immutable';
 
 const initialState = {
   modalType: null,
-  modalProps: {}
+  modalProps: {},
 };
 
 export default function modal(state = initialState, action) {