Fixes: FRMW-2974
Currently during the product imports, we create multiple chunks that must be deleted after the import has finished (either successfully or with an error). Deleting files one by one leads to multiple network calls and slows down everything.
The `bulkDelete` method deletes multiple files (with their fileKey) in one go
* feat: implement direct upload
* feat: add direct-upload endpoint
* refactor: implement feedback
* refactor: have a dedicated endpoint for direct uploads
* refactor: convert responses to snakecase
* refactor: rename method to createImport
* test: add tests for the presigned-urls endpoint
