Restructuring of the code. They have passed the data functions to the
model.
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)