Project Import from object storage via API
## Summary
Currently, the Infrastructure SRE team is frequently asked by Customer Support to run manual exports or imports because they fail due to an enforced size-limit on GitLab.com on http transfers via web and API. The SRE team can intercede by running the import/export on the Rails console and then providing customer support with the archives requested. But, it's an extremely inefficient process that would be better performed self-service by our customers or Customer Support GitLab.com Administrators.
## Proposed solution
Per [this note](https://gitlab.com/gitlab-org/gitlab/-/issues/282503#note_506887980), we will enable project owners to add credentials and a storage path to import an archive of their project. Following the :footprints: iteration value, we will do this via API, the same way we already have in the project export.
## Future considerations
This issue only adds the import storage credentials to the API. As a future iteration, we may expose this feature in the UI.
## Definition of Done
- [x] Project owners can add credentials and a storage path to export an archive of their project. This is already available via API.
- [ ] Same as above, but to import an archive of their project. (this issue)
issue