Updating api crossref gets to have timeouts and response handling

Jose Marquez Prietorequested to merge
Updating_API_crossref into develop

The ELN base class PublicationReference has calls to retrieve data from the crossref API. This merge request set timeouts and a mailto within the request.get to fall into polite pool. This was necessary because the external API has ofter some downtime that gets the processing of the uploads stuck.

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