Add Dataset draft downloading

[Pranjalya]

Allow downloading of unpublished draft dataset and its data files using the API token and its access credentials.

[skasberger]

Thanks for your issue. I will have a look at the API, if this is even possible. Had some problems in the past with filtering results for versions and/or published/draft state. Sometimes this is not possible, but let's see.

[pdurbin]

As discussed during the 2024-02-14 meeting of the pyDataverse working group, we are closing old milestones in favor of a new project board at https://github.com/orgs/gdcc/projects/1 and removing issues (like this one) from those old milestones. Please feel free to join the working group! You can find us at https://py.gdcc.io and https://dataverse.zulipchat.com/#narrow/stream/377090-python