Add associated DOIs to response

[lukasheinrich]

Hi,

more ideas :)

We are in the process of integrating with services that will associated DOIs. We would like to be able to associate a DOI at two places:

1. at request creation/update:
   a DOI will be minted for the request made by the "theorist" and will be associated to the original paper that motivated the request. probably the right place to add this is in the "Update a Request/Create a Request" API endpoints. In the end a request should have a new property, perhaps called 'recast-request-doi' (to differentiate it with a possible doi for its reference

2. when uploading a response

a response should likewise have a 'recast-response-doi' which will be minted as a supplement to the underlying analysis

Thanks,
Lukas