Adds Vagrant supported by Puppet

This allows to completely reproduce a dev environment within a few minutes.
Removes the dependencies from the repository

Instead, a script is used to fetch them. Documentation has to be added to
explain exactly how to use vagrant, this script will have to be included in it.
Merge remote-tracking branch 'ralt/master' into vagrant
Adds the vagrant set up documentation.
Adds the postgresql credentials to the documentation
Clean up the Vagrantfile.
Moves vagrant-related folders/files in its own folder.
Merge remote-tracking branch 'ralt/master' into vagrant
just changed a word in readme