Move index.js to web_src and use webpack to pack them (#8598)

* Move index.js to web_src and use webpack

* Fix initHeatMap

* update eslint and move webpack to devDependencies

* update index.js

* add eslint env node

.eslintrc

@@ -10,6 +10,7 @@ env:
   browser: true
   jquery: true
   es6: true
+  node: true
 
 globals:
   Clipboard: false