Error with the 'npm run start" in current release

I got an error message when performing the following steps:
```
git clone ...
npm install
npm run build
npm run start
```
The `npm run start` command printed the following error message:
`Error: Cannot find module 'webpack-cli/bin/config-yargs'`

It seems to be a problem of incompatibility between the webpack, webpack-cli and the webpack-dev-server versions. I downgraded the webpack and webpack-cli and this problem was gone.

Clone the repository, run the reported npm install, npm run build, and npm run start sequence, and confirm the webpack-cli/bin/config-yargs error. Then inspect the webpack, webpack-cli, and webpack-dev-server dependency versions and their package configuration; done means a clean install can start successfully without the missing-module error.

Scritto dal modello di indicizzazione a partire dal testo della issue.