As a user I want to use S3 browser so that I can manage my buckets and objects via DLab UI.
1. User has access endpoint_shared bucket and project bucket (only if he is assigned to this project)
2. Another user does not have access to project bucket (if he is not assigned to this project)
3. Administrator has access to all buckets
4. User can upload and download files to and from bucket
5. User can create public URLs to share the files
6. User can set Access Control on buckets and files only for project bucket?