Revert "Temporarily remove translations."

This reverts commit 74a285322d0d1606245f7571b1d1d2c10d3ba360.
Update the Italian translation from Transifex.

Thanks to Toky Soloniaina.
Temporarily remove most translations.

Because, apart from Italian, the only finished app translation
(German) doesn't have a finished decision-tree (website) translation,
and the only finished decision-tree (website) translations
don't have finished app translations.

Hopefully more app translations will be ready soon. Then I can
revert this commit.
Fix tiny typo in a comment.