### What problem does this PR solve?
Avoid getting doc in function delete_document_metadata as the doc might
have been removed.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
Put document metadata in ES/Infinity.
Index name of meta data: ragflow_doc_meta_{tenant_id}
### Type of change
- [x] Refactoring
### What problem does this PR solve?
Manage message and use in agent.
Issue #4213
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
- Admin client support drop user.
Issue: #10241
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
- Admin client support show user and create user command.
- Admin client support alter user password and active status.
- Admin client support list user datasets.
issue: #10241
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
