Implement Azure Files backend

Co-authored-by: moongdal <moongdal@tutanota.com>

docs/content/azurefiles.md

@@ -0,0 +1,21 @@
+---
+title: "Microsoft Azure Files Storage"
+description: "Rclone docs for Microsoft Azure Files Storage"
+---
+
+# Microsoft Azure File Storage
+
+
+### Modified time
+
+Stored as azure standard `LastModified` time stored on files
+
+### Hashes
+
+MD5 hashes are stored with files.
+
+### Authentication {#authentication}
+
+1. ConnectionString
+2. Accout and Key
+3. SAS URL