Following !373

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

1. Install zanata-cli on your computer
(https://zanata.readthedocs.io/en/latest/client/installation/linux-installation/)
2. Configure zanata-cli
(https://zanata.readthedocs.io/en/latest/client/configuration/)
3. Do your stuff, add your new strings to locale/en.json only
4. Push the new locales: make push-locales
5. Translate on https://trad.framasoft.org
6. Pull the new locales: make pull-locales (requires the Perl module
JSON, provided by libjson-perl on Debian)
7. Commit and enjoy