Update render module of centos-art.sh script.
    
    - Previously, render module was using the TARGET variable name to
      store the final location where files will be stored in. This update
      change the variable name from TARGET to RENDER_TARGET to make it
      clear it refers to render module.
    
    - Add missing tcar_checkRepoDirSources verification when assigning
      positional parameters.
    
    - Previously, when producing content through extended rendition, final
      files in English language are stored inside the Images directory and
      files in non-English languages are stored inside a language-specific
      directory inside the Images directory. This update uses the
      Final/${TCAR_SCRIPT_LANG_LC} directory structure for final files in
      both English and non-English languages.
    
    - Add --no-locale-dir option. This option let you control whether
      final content is produced inside language-specific directories or
      not. By default final content is stored inside language-specific
      directories.
    
    - Previously, the render_setLocalizedXml function was using SOURCES
      name variable instead of SOURCE variable name. This made the whole
      localization process to fail because no file was found for
      processing. This update changes the render_setLocalizedXml function
      to use SOURCE variable name instead of SOURCES.
    
    - Previously, the render_setLocalizedXml function didn't verify
      existence of the translation files it works with. This update
      changes render_setLocalizedXml to verify existence of translation
      files before processing them.
    
    - Previously, the render_setLocalizedXml function moved into
      directory holding localization files at the exact time of producing
      the localized xml with the intention of finding the files relatively
      referred inside the xml file. However those files aren't stored in
      the localziation directory but inside the final render location.
      This update changes the render_setLocalizedXml function to move into
      final render location instead of localization location.