Move index.js to web_src and use webpack

Author: lunny

.eslintrc.json

@@ -0,0 +1,5 @@
+{
+    "env": {
+        "es6": true
+    }
+}

Makefile

@@ -434,7 +434,8 @@ npm-update: npm-check
 
 .PHONY: js
 js: npm
-	npx eslint public/js
+	npx eslint web_src/js webpack.config.js
+	npx webpack
 
 .PHONY: css
 css: npm

package-lock.json

@@ -12,12 +12,16 @@
     "postcss-cli": "6.1.3",
     "stylelint": "10.1.0",
     "stylelint-config-standard": "18.3.0",
-    "updates": "8.5.3"
+    "updates": "8.5.3",
+    "webpack-cli": "3.3.10"
   },
   "browserslist": [
     "> 1%",
     "last 2 firefox versions",
     "last 2 safari versions",
     "ie 11"
-  ]
+  ],
+  "dependencies": {
+    "webpack": "4.41.2"
+  }
 }