We changed the way we upload the translations to
Crowdin, some translations were missing for the
email templates. We add them back and improve
the tests to make sure we don't forget them again.
The email was branded "La Suite Numérique",
we updated the template to make it generic, we
will use settings env variables to customize the
email for each brand.
Change the email invitation content. More
document related variables are added.
To benefit of the document inheritance, we moved
the function email_invitation to the document model.
