Transfer artifacts to object storage after storing

What does this MR do?

After a build is finished, it schedules the artifact for uploading to an object storage.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• [-] API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• [-] Conform by the merge request performance guides
• [-] Conform by the style guides
• [-] Branch has no merge conflicts with master (if it does - rebase it please)
• [-] Squashed related commits together

What are the relevant issue numbers?

Fixes gitlab-org/gitlab-ee#3346