Take full advantage of object storages

[CarlSchwan]

When we are using an object store and not using server side encryption, Nextcloud clients (web/desktop/...) should do as many operation as possible directly on the object store without relying on Nextcloud. This is possible thanks to pre-signed links which allow to do some operation for a certain amount of time.

Must have (P0/S)

• [x] Download files from S3 directly #54436
  • [x] Support for desktop client
  • [ ] Support for web client
  • [ ] Support for iOS client
  • [ ] Support for Android client
• [ ] Download files from S3 to generate previews #53634
• [ ] Download previews from S3 directly #54622

Nice to have (P2/M)

• [ ] Upload files to S3 directly