adding support for download\batchdownload from data management api

[RomanIvn]

https://forge.autodesk.com/en/docs/data/v2/reference/http/buckets-:bucketKey-objects-batchsigneds3download-POST/

Any implementation?

[Magnus-COWI]

There is for uploading. Maybe you can use that for inspiration?
https://github.com/petrbroz/forge-sdk-python/blob/develop/src/autodesk_forge_sdk/datam.py#L380-L417