Add endpoint to download single artifact by ref
What does this MR do?
Add a new endpoint that can be used to download a single file from artifacts for the specified ref and job.
What are the relevant issue numbers?
Follow up for documentation changes https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/23581
Does this MR meet the acceptance criteria?
- Changelog entry added, if necessary
- Documentation created/updated
- Tests added for this feature/bug
- Conforms to the code review guidelines
- Conforms to the merge request performance guidelines
- Conforms to the style guides
- Conforms to the database guides
- Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
- Security reports checked/validated by reviewer
Closes #54626 (closed)