Add preloader for site front layout

package.json

@@ -4,6 +4,7 @@
   "description": "",
   "scripts": {
     "watch": "webpack --mode=development --watch -d",
+    "start": "npm run watch",
     "build": "webpack --mode=production"
   },
   "author": "",

project/app/static/webpack_sources/js/index.js

@@ -2,5 +2,6 @@
 import "../scss/index.scss";
 
 // Js
-import "./home_page.js";
-import "./ho_dan.js";
+import "./home_page";
+import "./ho_dan";
+import "./preloader"

project/app/static/webpack_sources/js/preloader.js

@@ -0,0 +1,14 @@
+import $ from 'jquery';
+
+const waitWebpackAndStyleLoader = 1100;
+
+// End preloader when webpack is ready
+$(document).ready(() => {
+  setTimeout(() => {
+    $('#loader').slideUp("fast", () => {
+        $('body').removeClass('cuuhomientrung__preloader');
+        $('#loader').remove();
+        $('#loader__wrapped').show();
+    });
+  }, Math.floor(Math.random() * waitWebpackAndStyleLoader));
+});