Support pregnancy extension table (PET)

[ginberg]

For pregnancy studies, a separate table is used (for now), the pregnancy extension table (PET). In the long term, this table will not be used anymore (will be moved to episode table), but for current studies it can still be useful

Request made by @Braventos

[cebarboza]

Hi @ginberg @Braventos

I'll try to implement something quick for this. I think is just adding the name of the table, columns and their corresponding data type to the json schema.

Could you send me an example of the table? Any Excel with some test data is ok.

[ginberg]

@cebarboza see attached the pregnancy sheet

TestData_Study_v1.xlsx