Vagrant box provisioning: fix nodejs-related packages (nodejs, yarn, npm)
Vagrant box provisioning: fix nodejs-related packages (nodejs, yarn, npm)

- yarn needs to be installed
- nodejs on Trusty is tool old to work with yarn
- npm conflicts with yarn

phusion/passenger,phusion/passenger,phusion/passenger,phusion/passenger,phusion/passenger,phusion/passenger,phusion/passenger,phusion/passenger