[tor-l10n] New staging for translations

[tor l10n team]

Fellow translators:

Yes! The new previews are working now at:

* tor browser manual: https://review.torproject.net/tpo/web/manual/l10n/
* support: https://review.torproject.net/tpo/web/support/l10n/
* main website: https://review.torproject.net/tpo/web/tpo/l10n/
* community: https://review.torproject.net/tpo/web/community/l10n/
* gettor website: https://review.torproject.net/tpo/web/gettor-web/l10n/


They are triggered when we notice updates from transifex on resources
that have at least 15% translation.

For more information you can read:

https://gitlab.torproject.org/tpo/community/l10n/-/wikis/Localization-for-translators