the list of archaeological features associated with the samples is recorded in three columns:
- Anlnr (e.g. A9, A256, R2) = feature_name, which goes in this Entity
- anlaggning (e.g. Stolphål, Brunn) = feature_type_name, which is part of Entity feature_types
- fornlamningstyp (e.g. boplats, hög, härd)
- create a data-derived entity features, with feature_id
- join it with the feature_type list based on the column anlaggning
