Remove help functionality from centos-art.sh script.
    
    - Before discovering Asciidoc, the help functionality was thought to
      reduce the number of actions required to write documentation in a
      standard way using different formats like Texinfo and Docbook. But
      now, that Asciidoc is being adopted as default documentation format
      inside the repository there is really no need of a help
      functionality. Asciidoc is so simple to write and structure that
      there is no need of a tool for such tasks. All documentation related
      to Texinfo format should be removed as well.