refactor code (#583)

### What problem does this PR solve?

### Type of change

- [x] Refactoring

rag/utils/__init__.py

@@ -15,9 +15,6 @@ def singleton(cls, *args, **kw):
     return _singleton
 
 
-from .minio_conn import MINIO
-from .es_conn import ELASTICSEARCH
-
 def rmSpace(txt):
     txt = re.sub(r"([^a-z0-9.,]) +([^ ])", r"\1\2", txt, flags=re.IGNORECASE)
     return re.sub(r"([^ ]) +([^a-z0-9.,])", r"\1\2", txt, flags=re.IGNORECASE)