Fix import localization files script

[data-sync-user]

Changing the base locale to be en-US invalidated the import localization automation.

This task is to fix the localization import and adapt it to new base locale en-US

At the moment the import is failing since in firefoxios-l10n the file are still kept with en as translation file directory, so when importing Xcode doesn’t find those files and fails to import new translations.

The LocalizationTools repo has been changed to address the locale change together with the firefoxios-l10n repo.

• Localization tools changes PR
• Added rewrite_original_attribute.py to prepare all Xliff file before import. new file

This task is to fix locale import by changing the related Firefox ios: import strings action with the new rewrite_original_attribute.py.

┆Issue is synchronized with this Jira Task