refactor code (#583)

### What problem does this PR solve?

### Type of change

- [x] Refactoring

rag/utils/minio_conn.py

@@ -8,7 +8,7 @@ from rag.utils import singleton
 
 
 @singleton
-class HuMinio(object):
+class RAGFlowMinio(object):
     def __init__(self):
         self.conn = None
         self.__open__()
@@ -86,10 +86,12 @@ class HuMinio(object):
                 time.sleep(1)
         return
 
-MINIO = HuMinio()
+
+MINIO = RAGFlowMinio()
+
 
 if __name__ == "__main__":
-    conn = HuMinio()
+    conn = RAGFlowMinio()
     fnm = "/opt/home/kevinhu/docgpt/upload/13/11-408.jpg"
     from PIL import Image
     img = Image.open(fnm)