Bug 16554: rewrite mandatory and sample data - de-DE

Bug 16554: rewrite mandatory and sample data - de-DE

More changes to de-DE files

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit 9261fb4f5bd6fd4b25ce97de7be9262b3719544a)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
(cherry picked from commit f37cbb96f2a24cc90619089033e7ec4074856a3d)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>