sd signature line: implement non-empty geometry during pdf sign
Parse the pdf output which contains just the signature line shape on a
page, take the same from it and use it at both places where previously
the position / size was just a stub.
(cherry picked from commit
4db25ccc736185c304f1bd090b8539868932700a)
Conflicts:
include/vcl/filter/pdfdocument.hxx
Change-Id: Ifb2e0ebf7b3514ee027701b9bf360a0c996cdc82
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/97246
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>