Use minio for static and media files

[jfilter]

Use the existing minio service (by our hoster) for static and media files. Use one of the s3-compliant storage backend:

• https://github.com/etianen/django-s3-storage
• https://github.com/jschneier/django-storages

Alternatively, something tailored for minio:

• https://github.com/theriverman/django-minio-backend
• https://github.com/py-pa/django-minio-storage (unmantained)