Investigate settings for audio/ consent / image uploads in deployment

[BeritJanssen]

In deployment, we bind-mount a directory from the host to lift the audio files into the server container. I noticed that the files uploaded via the admin interface do not appear in the host's directory. So we may actually not yet persist the files uploaded via the admin interface in a volume. This may not be an issue for the new deployment setup though, so this mainly serves as a reminder to:

• check files uploaded via admin on old servers (this mainly applies to the rhythm tests, which have a consent file uploaded attached that way)
• double-check that our new deployment setup correctly persists the uploaded files in a volume