enhancement request: add checks of CDM *_datetime fields

[TomWhite-MedStar]

Some data sources contain timestamp information and are able to populate the *_datetime fields. However, there is no easy way to assess which sources do so.

There are two classes of datetime rules that might be helpful:

1. Validation/Conformance (?): When datetime fields are populated, does their date component match that of the comparable date field? Possible rule: CAST(field_datetime AS DATE) = field_date
2. Validation/Completeness (?): When datetime fields are populated, do they have a non-zero time component? Possible rule: (CAST(field_datetime AS DATE) = field_date) AND (field_datetime > field_date)

This information would be helpful for:

• Internal ETL efforts
• External sharing of profiled datasets so that network users know which data sources are possible candidates for phenotypes and analyses that require datetime logic.