Update icon-poweredby.svg:
    
        - Start using 204c8d color as background.
    
        - Set The CentOS Symbol to 22x22 pixels of dimension. The word
          CentOS is align bottom and the `Powered by' string to top, using
          The CentOS Symbol as reference.
    
        - The `Powered by' string is no longer in bold face. That make the
          string wider and steals some space that we can use as regular
          font face.