Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This adds support for AWS S3 SSE with S3 managed keys, this means the data is encrypted at rest and the encryption is handled transparently to the end user as well as in the AWS Console.
I'm unsure on the best way to the handle the default. I've followed the multipart_upload de facto in the app. I'm happy to change this if required or if it will impact elsewhere e.g. omnibus packages
I also think I've managed to catch all of the documentation for this change as well.
Many enterprises require good backup support but also for this to be encrypted. By default backups aren't encrypted, this allows at rest encryption to be supported in GitLab backups providing a layer of security should the physical media not be properly disposed of.
Relates to issue #2478 (closed).