🌐(backend) adding de_DE translation for the backend

This adds German translation to the backend and
adjusts the .po file sequence by priority.

Signed-off-by: lindenb1 <linden@b1-systems.de>

src/backend/impress/settings.py

@@ -237,6 +237,7 @@ class Base(Configuration):
         (
             ("en-us", _("English")),
             ("fr-fr", _("French")),
+            ("de-de", _("German")),
         )
     )