Missing `BACKEND_MEDIA_ROOT` in `.env.dist`

[Lugrim]

When running current dev version with .env.dist as .env, we have

Please add it with a description of what the value is, what it should look like, and setting its default to something working out-of-the-box for a dev environment

[Dyskal]

ATM, the meaning of BACKEND_MEDIA_ROOT / BACKEND_STATIC_ROOT are for the MEDIA_ROOT / STATIC_ROOT Django settings, and are set to : v1/${...}.

According to Django, they are :

• The filesystem path to the directory that will hold user-uploaded files.
• The path to the directory where collectstatic will collect static files for deployment. Which are currently the static files for Django admin views and DRF browsable api.

They are served at v1/static because Django serve ${WEBSITE_HOST}/v1/...