doc: Scute can be used to sign documents.
* doc/manual/scute.texi: Explain how to use Scute with LibreOffice. * doc/manual/libreoffice-certificate-selection.png: New image. * doc/manual/libreoffice-digital-signatures.png: New image. * doc/manual/libreoffice-pdf-signature.png: New image. * doc/manual/Makefile.am: Include the new images. * README: Mention that Scute can work with LibreOffice. * doc/website/index.xhtml: Likewise.
- Signed-off-by: Damien Goutte-Gattat <dgouttegattat@incenp.org>
