add typecodes enpoint

unauthenticated.

closes #385

nmdc_runtime/api/endpoints/nmdcschema.py

@@ -2,6 +2,8 @@
 
 import pymongo
 from fastapi import APIRouter, Depends, HTTPException
+
+from nmdc_runtime.minter.config import typecodes
 from nmdc_runtime.util import nmdc_database_collection_names
 from pymongo.database import Database as MongoDatabase
 from starlette import status
@@ -37,6 +39,11 @@ def get_nmdc_schema_version():
     return version("nmdc_schema")
 
 
+@router.get("/nmdcschema/typecodes")
+def get_nmdc_schema_typecodes():
+    return typecodes()
+
+
 @router.get("/nmdcschema/collection_stats")
 def get_nmdc_database_collection_stats(
     mdb: MongoDatabase = Depends(get_mongo_db),