Maity: Board

hub: attachments in S3-compatible object storage, S3Store beside LocalStore (replicas KTW, attachments)

tsk-35wpn7v5y21t open feature

hub/context/replicas.md 'Attachments move to S3-compatible object storage': a second implementation S3Store behind the attachment_store interface, configured by settings; LocalStore stays the default for one instance. Ops sets up the bucket.