milvus: New langchain_milvus package and new milvus features (#21077)

New features:

- New langchain_milvus package in partner
- Milvus collection hybrid search retriever
- Zilliz cloud pipeline retriever
- Milvus Local guid
- Rag-milvus template

---------

Signed-off-by: ChengZi <chen.zhang@zilliz.com>
Signed-off-by: Jael Gu <mengjia.gu@zilliz.com>
Co-authored-by: Jael Gu <mengjia.gu@zilliz.com>
Co-authored-by: Jackson <jacksonxie612@gmail.com>
Co-authored-by: Erick Friis <erick@langchain.dev>
Co-authored-by: Erick Friis <erickfriis@gmail.com>

libs/community/langchain_community/vectorstores/milvus.py

@@ -5,6 +5,7 @@ from typing import Any, Iterable, List, Optional, Tuple, Union
 from uuid import uuid4
 
 import numpy as np
+from langchain_core._api.deprecation import deprecated
 from langchain_core.documents import Document
 from langchain_core.embeddings import Embeddings
 from langchain_core.vectorstores import VectorStore
@@ -22,6 +23,11 @@ DEFAULT_MILVUS_CONNECTION = {
 }
 
 
+@deprecated(
+    since="0.2.0",
+    removal="0.3.0",
+    alternative_import="langchain_milvus.MilvusVectorStore",
+)
 class Milvus(VectorStore):
     """`Milvus` vector store.