<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Work on this issue](https://contributors.gitlab.com/manage-issue?action=work&projectId=278964&issueIid=379216) - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=379216) </details> <!--IssueSummary end--> As discussed in POC https://gitlab.com/gitlab-org/gitlab/-/issues/376261 GitLab Migration should start exporting relations compressed with zip. ### Proposed solution 1. Update `API::GroupExport` & `API::ProjectExport` to accept new optional query param `use_zip = true` 2. Update `BulkImports::RelationExportService` to utilize this flag and export relations compressed in zip if `use_zip = true` 3. If flag is missing or `false`, use old exporting logic of exporting in `tar.gz` format 4. Decompressed contents should remain identical to ones from `tar.gz` to be able to process data on Import side without any changes to directory/file structure