Add mimic-iii concepts to sqlglot transpilation

[alistairewj]

Mostly works but needs some custom args:

mimic_utils convert_folder mimic-iii/concepts mimic-iii/concepts_duckdb \
  --destination_dialect duckdb \
  --derived_schema mimiciii_derived \
  --schema_map mimiciii_clinical=mimiciii,mimiciii_notes=mimiciii \
  --exclude cookbook other-languages functions pivot/pivoted_oasis.sql

mimic_utils convert_folder mimic-iii/concepts mimic-iii/concepts_postgres \
  --destination_dialect postgres \
  --derived_schema mimiciii_derived \
  --schema_map mimiciii_clinical=mimiciii,mimiciii_notes=mimiciii \
  --exclude cookbook other-languages functions pivot/pivoted_oasis.sql