Split CONCEPT_RECORD_COMPLETENESS for required vs non-required

[MaximMoinat]

The CONCEPT_RECORD_COMPLETENESS check has become complex, implementing separate logic for required and non-required _concept_id fields.

We can have two checks:

• CONCEPT_RECORD_0_COMPLETENESS, violates if _concept_id = 0 for required fields
• CONCEPT_RECORD_NULL_COMPLETENESS, violates if _concept_id = 0 or _concept_id IS NULL for non-required fields when respetive _source_value is given.
  (requires a separate parameter "source field" per concept field

See discussion on field_concept_record_completeness.sql in PR #618: https://github.com/OHDSI/DataQualityDashboard/pull/618/files/f10acc0ba7393e8981e47317e3d196939a93979f#r2255653119