lib: Add new modules

lib: Add new modules

In an effort to move out as much as possible from the main script, we create
these modules to host the methods.

* LangHandling: This module host all the functions for handling
  languages (functions that define obj directories of the language, rewrite
  the file extention...).
* SilentRules: Declares functions for handling silent rules.
* Requires: Functions for requiring configuration files.