[Bug]: <title>failed to delete doc by id: some functions are not implimented

[KangCaijun]

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• I have searched the existing issues and this bug is not already filed.
• I believe this is a legitimate bug, not just a question or feature request.

Describe the bug

I used the git main branch with MongoKVStorage, MongoDocStatusStorage, QdrantVectorDBStorage and Neo4JStorage.
and the demo code as below:

        try:
            # 检查文档是否存在
            doc_status = await rag.doc_status.get_by_id(doc_id)
            if not doc_status:
                raise HTTPException(
                    status_code=404,
                    detail=f"Document with ID '{doc_id}' not found"
                )

            # 删除文档及其相关数据
            await rag.adelete_by_doc_id(doc_id)
            
            return InsertResponse(
                status="success",
                message=f"Document '{doc_id}' and its related data deleted successfully"
            )
        except Exception as e:
            logger.error(f"Error DELETE /documents/{doc_id}: {str(e)}")
            logger.error(traceback.format_exc())

And I got these error:

heai_kb    | Traceback (most recent call last):                                                                                                                                                                                                                             
heai_kb    |   File "<frozen runpy>", line 198, in _run_module_as_main
heai_kb    |   File "<frozen runpy>", line 88, in _run_code                                                                                                                                                                                                                 
heai_kb    |   File "/app/lightrag/api/lightrag_server.py", line 600, in <module>                                                                                                                                                                                           
heai_kb    |     main()                                                                                                                                                                                                                                                     
heai_kb    |   File "/app/lightrag/api/lightrag_server.py", line 577, in main                                                                                                                                                                                               
heai_kb    |     app = create_app(args)
heai_kb    |           ^^^^^^^^^^^^^^^^                                                                                                                                                                                                                                     
heai_kb    |   File "/app/lightrag/api/lightrag_server.py", line 314, in create_app                                                                                                                                                                                         
heai_kb    |     rag = LightRAG(                                                                                                                                                                                                                                            
heai_kb    |           ^^^^^^^^^
heai_kb    |   File "<string>", line 37, in __init__                                                                                                                                                                                                                        
heai_kb    |   File "/app/lightrag/lightrag.py", line 387, in __post_init__                                                                                                                                                                                                 
heai_kb    |     self.entities_vdb: BaseVectorStorage = self.vector_db_storage_cls(  # type: ignore                                                                                                                                                                         
heai_kb    |                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                                                                                                                                                                         
heai_kb    |   File "/app/lightrag/utils.py", line 890, in import_class
heai_kb    |     return cls(*args, **kwargs)                                                                                                                                                                                                                                
heai_kb    |            ^^^^^^^^^^^^^^^^^^^^                                                                                                                                                                                                                                
heai_kb    | TypeError: Can't instantiate abstract class QdrantVectorDBStorage with abstract methods get_by_id, get_by_ids   

When I review the code, I find that "QdrantVectorDBStorage .get_by_id", "QdrantVectorDBStorage .get_by_ids" , "QdrantVectorDBStorage.client_storage", "MongoKVStorage.get_all", "MongoKVStorage.delete" and "MongoDocStatusStorage.delete" are not implemented. So the function "adelete_by_doc_id" is completely unusable.

Steps to reproduce

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Expected Behavior

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LightRAG Config Used

Paste your config here

Logs and screenshots

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Additional Information

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• Python Version:
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