extract events from the discharged_concept_id field of the visit table

[ChaoPang]

We want to extract discharged_concept_id as a separate event from the visit table. This will be important for identifying hospital discharge events to use ACES.

[EthanSteinberg]

Did you verify that this works? I think you need the file suffix thing for the discharged_to_concept_id field as well?

[ChaoPang]

@EthanSteinberg I ran this successfully on Columbia data, I didn't add file suffix because it uses the first table_details in the list to return all the files at https://github.com/Medical-Event-Data-Standard/meds_etl/blob/main/src/meds_etl/omop.py#L718, but I am happy to add the file_suffix to discharged_to_concept_id for consistency.

[EthanSteinberg]

Oh, I didn't know that it uses the first one. That's a bit confusing. Thanks for adding and testing this!

Feel free to merge whenever you are ready.