Add uglifyjs plugin (#2070)

* Add uglifyjs plugin and replace -p flag with --env.production
* Add uglifyjs plugin
* Configure UglifyJsPlugin to drop console and prevent eslint error
* Turn off no-console rule because uglifyjs plugin drops it in prod

.eslintrc.js

@@ -32,7 +32,7 @@ module.exports = {
     ]
   },
   "rules": {
-    "no-console": process.env.NODE_ENV === 'production' ? 2 : 0,
+    "no-console": 0,
     "comma-dangle": [
       "error",
       {