Plausible before birth checks

[MelaniePhilofsky]

First, thank you @katy-sadowski, @MaximMoinat and all who update, maintain and support the DQD! This is a very useful tool and we rely on it to ensure our data are of high quality.

One suggestion, the new plausible before birth checks require an even start before birth. However, in our source data some of our events start at birth. So, a baby has a birthdatetime of 10am on December 31, 2024, their visit_start_datime is also at 10am on December 31, 2024. The DQD requires birthdatetime < visit_start_datime. I think changing the check of birthdatetime < or = visit_start_datime would be more appropriate since visits (and possibly other clinical events) can start at birthdatetime.