Addressing issues with abnormal labs from MEDS-DEV

[gkondas]

As discussed here, ACES doesn't currently support the default task configurations for many of the abnormal labs tasks on MEDS-DEV. This is due to the fact that derived predicates involving range only plain predicates are currently not supported due aggregation by (subject_id,timestamp) of the predicates_df before evaluation of derived predicates.

To address this I see three main paths foward:

1. ACES fully adds support for null code/ range only predicates involved in derived predicates. This will require re-ordering of operations inside get_predicates_df() as discussed here.

2. Use code inheritance in predicates. This will however require complex changes to ACES but would not change the ACES API guarantees.

3. Revert to older style mandating that ranges are present in dataset predicate files for now.