Add visual style customization for httpd-2.2.3-74.el5.
    
    - The customization committed here is focused in error screens and
      directory-listing screens produced by httpd. The customization uses
      The CentOS Project corporate visual style.
    
    - The customization committed here, onces installed, will survive
      updates of httpd package because we set the configuration stuff in
      our own configuration file (webenv.conf) under /etc/httpd/conf.d/
      directory and move out all the errors, images and indexes stuff out to a
      directory (/var/www/webenv) of their own. Such directory is aliased
      in webenv.conf file so its content can be accessible.
    
    - The customization committed here makes use of httpd server side
      includes (SSI) to display dynamic content.  When httpd does
      directory listing, we use SSI to read the REQUEST_URI variable,
      provide localization to "Index of" phrase and print the current year
      at page bottom (near the copyright word). When httpd prints error
      screens, we use SSI to show localization messages using httpd
      default messages.