Investigate use of dates vs timestamps for intermediate entity derivation / de-duping logic

[katy-sadowski]

For example, condition costs are identified via a join on date time right now; maybe this should be date?

dbt-synthea/models/intermediate/int__cost_condition.sql

Line 44 in ae79114

AND e.encounter_start_datetime = ca.service_datetime

ETL-Synthea truncates datetimes to dates, so not an issue there. It's possible it doesn't make sense to join on a timestamp. Need to look in the data to confirm.

Also, the issues in #47 turned out to be related to ordering of visit events by date vs datetime.