Storage: Support the s3, azure blob as the object storage of ragflow. (#2278)

### What problem does this PR solve?

issue: https://github.com/infiniflow/ragflow/issues/2277

_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._

### Type of change

- [ ] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

rag/utils/azure_sas_conn.py

@@ -0,0 +1,80 @@
+import os
+import time
+from io import BytesIO
+from rag import settings
+from rag.settings import azure_logger
+from rag.utils import singleton
+from azure.storage.blob import ContainerClient
+
+
+@singleton
+class RAGFlowAzureSasBlob(object):
+    def __init__(self):
+        self.conn = None
+        self.container_url = os.getenv('CONTAINER_URL', settings.AZURE["container_url"])
+        self.sas_token = os.getenv('SAS_TOKEN', settings.AZURE["sas_token"])
+        self.__open__()
+
+    def __open__(self):
+        try:
+            if self.conn:
+                self.__close__()
+        except Exception as e:
+            pass
+
+        try:
+            self.conn = ContainerClient.from_container_url(self.account_url + "?" + self.sas_token)
+        except Exception as e:
+            azure_logger.error(
+                "Fail to connect %s " % self.account_url + str(e))
+
+    def __close__(self):
+        del self.conn
+        self.conn = None
+
+    def health(self):
+        bucket, fnm, binary = "txtxtxtxt1", "txtxtxtxt1", b"_t@@@1"
+        return self.conn.upload_blob(name=fnm, data=BytesIO(binary), length=len(binary))
+
+    def put(self, bucket, fnm, binary):
+        for _ in range(3):
+            try:
+                return self.conn.upload_blob(name=fnm, data=BytesIO(binary), length=len(binary))
+            except Exception as e:
+                azure_logger.error(f"Fail put {bucket}/{fnm}: " + str(e))
+                self.__open__()
+                time.sleep(1)
+
+    def rm(self, bucket, fnm):
+        try:
+            self.conn.delete_blob(fnm)
+        except Exception as e:
+            azure_logger.error(f"Fail rm {bucket}/{fnm}: " + str(e))
+
+    def get(self, bucket, fnm):
+        for _ in range(1):
+            try:
+                r = self.conn.download_blob(fnm)
+                return r.read()
+            except Exception as e:
+                azure_logger.error(f"fail get {bucket}/{fnm}: " + str(e))
+                self.__open__()
+                time.sleep(1)
+        return
+
+    def obj_exist(self, bucket, fnm):
+        try:
+            return self.conn.get_blob_client(fnm).exists()
+        except Exception as e:
+            azure_logger.error(f"Fail put {bucket}/{fnm}: " + str(e))
+        return False
+
+    def get_presigned_url(self, bucket, fnm, expires):
+        for _ in range(10):
+            try:
+                return self.conn.get_presigned_url("GET", bucket, fnm, expires)
+            except Exception as e:
+                azure_logger.error(f"fail get {bucket}/{fnm}: " + str(e))
+                self.__open__()
+                time.sleep(1)
+        return