Update `identity' functionality:
    
        - Prepare functionality to render both SVG and DocBook. These two
          structures are based on XML so they can be processed by xml2po
          to retrive translation messages. Main difference is in the way
          the final format is produced. In the case of SVG, Inkscape is
          used to produce PNG images from SVG design templates. In the
          case of Docbook, different commands are required. So this
          specific part of the flow was taken from common part and called
          using template instance extension as reference. When design
          templates are svg files, the svg production is called. When
          design templates are docbook files, the docbook production is
          called.
    
        - The following files has been updated:
            identity_renderDm.sh
            identity_getConfig.sh
            identity_renderBase.sh
            identity_renderKsplash.sh
            identity_renderPostActions.sh
            identity_renderLastActions.sh
    
        - The following files has been added:
            identity_renderSvg.sh
            identity_renderSvgPostActions.sh
            identity_renderSvgLastActions.sh