refactor rename add-data -> import

chromy/handlers/import_data.py

@@ -0,0 +1,9 @@
+from __future__ import annotations
+
+from chromy.utilities import ingest_file
+
+
+def handle_import(collection: str, file: str) -> int:
+    records_added = ingest_file(collection, file)
+    print(f"Added {records_added} records to collection '{collection}'.")
+    return 0