v1.5 taken from <https://dejure.org/vernetzung.html>
with author's consent.
Some minor changes to the database queries, trying
to be more compatible to other database backends,
see <https://board.s9y.org/viewtopic.php?f=10&t=21255>.
Update language files (as far as I speak those
languages).
Signed-off-by: Thomas Hochstein <thh@inter.net>