Documentation for bulk author import format

[palkerecsenyi]

Add CDS end-user documentation to explain the JSON format needed for bulk-importing authors on the deposit form. There is already an example JSON in the modal on the deposit form, but we should clarify any ambiguities and give a bit more explanation. See the parent issue for more details.

For now we could create this documentation in CDS and then later transfer to InvenioRDM if there's a demand for it.

[zeel2104]

Is it open for contribution?

[palkerecsenyi]

@zeel2104 No, sorry, not at the moment. We're still scoping out how we should document this and thinking about what information to include for our users. So we will update the issue with more details later. Thank you for your interest in contributing!