Update ETL to v5.4.2

[briangow]

In #40, we updated the DDL to Common Data Model (CDM) v5.4.2. This PR updates the ETL scripts to comply with CDM v5.4.2.

In two cases (visit_occurrence, visit_detail) some of the variable names were updated. In most cases, new variables were added to a given table. In this scenario, I generally added the variables and assigned NULL to the new value. Updates to add meaningful values to the new variables will be handled in separate PRs on a table by table basis. Here is a summary of the variables that were added and how they were updated/handled in this PR:

• table: device_exposure
  • variables: production_id, unit_concept_id, unit_source_value, unit_source_concept_id
  • updated: set as NULL. See Add unit information to device_exposure table #55 for details.
• table: location
  • variables: country_concept_id, country_source_value, latitude, longitude
  • updated: in this case the variables were updated with meaningful values. Since this seemed straight-forward and didn't require extensive changes, I went ahead and implemented it as part of this PR.
• table: measurement
  • variables: measurement_event_id, meas_event_field_concept_id
  • updated: set as NULL
• table: observation
  • variables: value_source_value, observation_event_id, obs_event_field_concept_id
  • updated: set as NULL
• table: procedure_occurrence
  • variables: procedure_end_date, procedure_end_datetime
  • updated: set as NULL. In this case I don't think the corresponding "start" variables are being set properly. See Need to properly set date / datetime fields in procedure_occurrence #54 for details.

There are some tables in v5.4.2 which aren't being built as part of the ETL. Adding the code to build these tables will also be handled in a separate PR.