refacto(Dockerfile): optimized with new setup

scripts/server-frontend-dev.js

@@ -1,7 +1,3 @@
-const webpack = require("webpack");
-const WebpackDevServer = require("webpack-dev-server");
-const config = require("../config/webpack.dev");
-
 const devServerConfig = {
   hot: true,
   inline: true,
@@ -19,6 +15,11 @@ const devServerConfig = {
 }
 
 function startFrontendDevServer(port) {
+  // require here to prevent prod dependency to webpack
+  const webpack = require("webpack");
+  const WebpackDevServer = require("webpack-dev-server");
+  const config = require("../config/webpack.dev");
+
   new WebpackDevServer(webpack(config), devServerConfig)
     .listen(port, (err) => {
       if (err) {