Translations: Run po4a/update-po and cleanup unused strings

Translations: Run po4a/update-po and cleanup unused strings

The v5.4 branch won't get any translation updates so the fuzzy
strings and obsolete strings are all useless. Cleaning them up
makes the files smaller.

    ./update-po

    for I in *.po
    do
        msgattrib --clear-fuzzy --clear-previous --empty \
                  --no-obsolete --no-wrap "$I" > tmp
        mv tmp "$I"
    done

The po4a run gave "Parse error at" message from fr.po but
after the fr.po was rewritten the error is gone.