Let's use the .nvmrc file to host the node version
If we add a file called .nvmrc with the node version nvm is going to handle the node version by it's own: https://github.com/creationix/nvm#nvmrc
So, with this file we can use nvm use or nvm install to use or install the right node version.
If this PR goes inside dropcat I think that we can delete the nodeVersion key from the package.jsonfile