Internationalization

[timadevelop]

Support multiple languages for responses

https://www.django-rest-framework.org/topics/internationalization/#internationalization

https://docs.djangoproject.com/en/2.2/topics/i18n/

• use _, ref: https://docs.djangoproject.com/en/1.7/topics/i18n/translation/
• make translations for Bulgarian language

[timadevelop]

use python manage.py compilemessages -l <locale>

[timadevelop]

Solved Docker issue for gettext: cookiecutter/cookiecutter-django#893