Review code style
Change enable "multilanguage Backend" metod to enableModule

Now looks more like your first method called enablePlugin.
Do not enable the language code plugin

As suggested by Jean Marie is not necessary to enable languagecode plugin when setting a multilang site. Its use is only to change the lang tag if desired (fr-FR to fr-BE for example)
Add recommendation to select no data for later multi language site creation
Merge pull request #1 from javigomez/installation-automatic-multilanguae-site2

Installation automatic multilanguae site2