[FIX] base: add German states

We need German states when formatting the 'SteurNummer'.
So we provide it so the user can select his, instead of having to
 create them by hand.

task-3056694
opw-2974560

closes odoo/odoo#111788

X-original-commit: c741637f
Related: odoo/enterprise#36649
Signed-off-by: William André (wan) <wan@odoo.com>
Signed-off-by: Wala Gauthier (gawa) <gawa@odoo.com>