Backport of fccfd36e05, 4ba7fbbf81 and 1421949c67 to saas-11.3
[FIX] tools: use pot as reference file
In the first attempt at #26134, the pot_targets was cleared after creating
the pot_rows object.
Since the rows not present in the pot_targets are now skipped, clearing the pot
should not be done.
Still use a temporary list pot_rows to avoid modifying the list we are iterating
on.
Update the .po test file to match the new file format
[FIX] tools: import translation file without pot
Due to fccfd36 and 4ba7fbb the translations were only imported, considering the
.pot as the reference.
During import or a manual csv or po file, there is no pot file.
Add tests with Klingon and Dothraki
Martin Trigaux
2de8998863