languages and codes for gnome

(in po directory) language codes should not duplicate language teams (this happening with de_DE.po and it_IT.po). This, after discussing in GNOME (https://mail.gnome.org/archives/gnome-i18n/2020-October/msg00052.html) And presenting the problem to GNOME Gitlab (https://gitlab.gnome.org/Infrastructure/damned-lies/-/issues/200#note_938227)