Remove Hardcoded entity list from map_data.py

[amc-corey-cox]

Make entity list configurable instead of hardcoded

Currently, map_data.py has a hardcoded entities list based on BDC requirements.

This limits the pipeline's reusability for other data models. Since dm-bip is built on LinkML, it would make sense to derive the entity list from the schema itself (e.g., using SchemaView to introspect classes) or make it configurable via a config file.