Chapter 4, node.js app inconsistency

Page 63, second edition ebook.

```
ansible-playbook playbook.yml \
--extra-vars="node_apps_location=/usr/local/opt/node"
```

This will not work OTB, missing inventory file.

Also this introduction with nodejs app is a bit confusing as relying only on book you will have to figure out how to reach the nodejs.test VM host (it is well explained in the git repo only).

Also` vagrant up` will provision everything as this is the setup in Vagrantfile. This chapter is not explaining this Vagrant setup and you introduce the provisioning here.

Review page 63 of the second-edition ebook alongside playbook.yml and Vagrantfile; first verify the missing inventory and provisioning behavior described in the issue. Check the repository's explanation of reaching the nodejs.test VM, then update the chapter so its commands, VM access, and Vagrant provisioning behavior are consistent and complete.

Written by the indexing model from the issue text.