Add Dandiset contributor roles

[kabilar]

As an aside, I am not sure if all of these roles make sense for a contributor so I have filed dandi/dandi-schema#365. We can update this list in the future based on the discussion in that issue.

[bendichter]

I'm fine with mentioning the roles if we are providing some explanation/best practices, but just as a list these roles are already available in the schema and in the meditor dropdown. I'm not sure what value it provides to duplicate them here.

[CodyCBakerPhD]

I think the most significant value to having them here would be to define what each means (for maximum clarity - e.g., what does the 'Methodology' role mean?) or to explain how to use them (as a Dandiset creator), or how to interpret them for data re-users who want to search/filter by some funder or contributor based on role

Funding information is among the most common questions we get for how to 'add it to Dandiset metadata'

[kabilar]

Thanks for the feedback. For my use case, I am requesting co-authors (who are not familiar with DANDI) to provide me with their roles for an upcoming Dandiset. I wanted to provide them a list of the possible roles, and figured that this might be better than providing them screenshots of the meditor dropdown menu or a link to the code on the dandi-schema repo.