Add further support for the [direct transfer API](https://docs.gitlab.com/ee/api/bulk_imports.html) (bulk imports). ## Implementation guide - Add new functions for each endpoint except the first one on the [direct transfer API](https://docs.gitlab.com/ee/api/bulk_imports.html) (bulk imports) to `bulk_imports.go`. - Add tests for each function to `bulk_imports_test.go`. - Run `make reviewable` and address any issues it raises. - Commit using semantic commit prefix `feat(bulk-imports):`.