l10n: de.po: translate 99 new messages

Translate 99 new messages came from git.pot update in
28b3cff (l10n: git.pot: v1.8.4 round 1 (99 new, 46 removed)).

Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com>
Acked-by: Thomas Rast <trast@inf.ethz.ch>