Fix running npm package forever in chapter 4

This addresses an issue in the nodejs example of chapter 4.
On some systems the path to the binary of the npm package 'forever'
might not be `/usr/local/bin/forever`.
Fixed by instead using `npx` to run it.

Author: Lukas-dev-threads

nodejs/provisioning/playbook.yml

@@ -38,10 +38,10 @@
       npm: "path={{ node_apps_location }}/app"
 
     - name: Check list of running Node.js apps.
-      command: /usr/local/bin/forever list
+      command: npx forever list
       register: forever_list
       changed_when: false
 
     - name: Start example Node.js app.
-      command: "/usr/local/bin/forever start {{ node_apps_location }}/app/app.js"
+      command: "npx forever start {{ node_apps_location }}/app/app.js"
       when: "forever_list.stdout.find(node_apps_location + '/app/app.js') == -1"