This is a temporary hotfix that allows to access build artifacts created
before 8.3. See #5257.
This needs to be changed after migrating CI build files.
Note that `ArtifactUploader` uses `artifacts_path` to create a storage
directory before and after parsisting `Ci::Build` instance, before and
after moving a file to store (save and fetch a file).
- Offloads uploading to GitLab Workhorse
- Use /authorize request for fast uploading
- Added backup recipes for artifacts
- Support download acceleration using X-Sendfile
