Add Rnotes directory structures:
    
        - Add trunk/Identity/Models/Tpl/Rnotes. This directory contains
          the release notes design templates in docbook format.
    
        - Add trunk/Locales/Identity/Models/Tpl/Rnotes. This directory
          contains the release notes translation messages in PO format.
    
        - Add trunk/Identity/Models/Img/Rnotes. This directory contains
          the final release notes files in XHTML and plain-text format.
          Files in this directory are used by `centos-release-notes'
          package.