adding hiera support for creating projects

This allows to create a load of projects creating a hash on hiera just includin the composer class.

E.g:

composer::projects:
  cli-generator:
    project_name: 'enxebre/cli-generator'
    target_dir: '/home/vagrant/cliGenerator'
  library:
    project_name: 'library
    target_dir: '/home/vagrant/library