Update centos-art.sh script's locale module.
    
    - Previously, script files do not have a top comment. This was with
      the intention of reduce the size of files. There were files that the
      top comment was larger than the code itself. Nevertheless, using the
      top comment grantee consistency along the script files making them
      visually connected, they provide a place for quick notes about what
      each specific file intend to do. The GNU License also says that:
    
        Cite: It is safest to attach them to the start of each source file
              to most effectively convey the exclusion of warranty; and
              each file should have at least the "copyright" line and a
              pointer to where the full notice is found.
    
      In this commit add the top comment back with function description,
      writer, copyright and license information in it.
    
    - Previously, asciidoc_convertAsciidocToDocbook was passing an empty
      value through --doctype option because RENDER_FLOW variable is not
      previously defined.  This commit removes the --doctype option
      altogether and leaves asciidoc to use its default value.
    
    - Previsouly, file.sh was poorly documented. Add comments to it.
    
    - Previsouly, update_convertXmlToPot was using a cat pipe xml2po
      construction. This is not necessary becase xml2po accepts a file for
      processing in its command line. This commit removes the cat pipe
      construction leaving just xml2po.