Throw an error when an assetId is already packaged.

[matvp91]

Describe the solution you'd like
We allow people to set an assetId in the package API call. We should schedule the job, and let Artisan check whether the assetId leads to a previously packaged asset and throw an error. We should only package assetId's that have not been packaged before.

Additionally, introduce a force flag on the package API endpoint to instruct Artisan to delete the folder with the assetId, no matter what. And repackage it.