S3 needs custom CORS rules

Custom CORS rules are currently required for the presigned URLs to work properly in fetch calls. The application could set these rules on startup.

{
  "CORSRules": [
    {
      "AllowedOrigins": ["https://comsol.svis.ethz.ch"],
      "AllowedHeaders": [],
      "AllowedMethods": ["GET"],
      "MaxAgeSeconds": 3000
    }
  ]
}