community[major], core[patch], langchain[patch], experimental[patch]: Create langchain-community (#14463)

Moved the following modules to new package langchain-community in a backwards compatible fashion:

```
mv langchain/langchain/adapters community/langchain_community
mv langchain/langchain/callbacks community/langchain_community/callbacks
mv langchain/langchain/chat_loaders community/langchain_community
mv langchain/langchain/chat_models community/langchain_community
mv langchain/langchain/document_loaders community/langchain_community
mv langchain/langchain/docstore community/langchain_community
mv langchain/langchain/document_transformers community/langchain_community
mv langchain/langchain/embeddings community/langchain_community
mv langchain/langchain/graphs community/langchain_community
mv langchain/langchain/llms community/langchain_community
mv langchain/langchain/memory/chat_message_histories community/langchain_community
mv langchain/langchain/retrievers community/langchain_community
mv langchain/langchain/storage community/langchain_community
mv langchain/langchain/tools community/langchain_community
mv langchain/langchain/utilities community/langchain_community
mv langchain/langchain/vectorstores community/langchain_community
mv langchain/langchain/agents/agent_toolkits community/langchain_community
mv langchain/langchain/cache.py community/langchain_community
mv langchain/langchain/adapters community/langchain_community
mv langchain/langchain/callbacks community/langchain_community/callbacks
mv langchain/langchain/chat_loaders community/langchain_community
mv langchain/langchain/chat_models community/langchain_community
mv langchain/langchain/document_loaders community/langchain_community
mv langchain/langchain/docstore community/langchain_community
mv langchain/langchain/document_transformers community/langchain_community
mv langchain/langchain/embeddings community/langchain_community
mv langchain/langchain/graphs community/langchain_community
mv langchain/langchain/llms community/langchain_community
mv langchain/langchain/memory/chat_message_histories community/langchain_community
mv langchain/langchain/retrievers community/langchain_community
mv langchain/langchain/storage community/langchain_community
mv langchain/langchain/tools community/langchain_community
mv langchain/langchain/utilities community/langchain_community
mv langchain/langchain/vectorstores community/langchain_community
mv langchain/langchain/agents/agent_toolkits community/langchain_community
mv langchain/langchain/cache.py community/langchain_community
```

Moved the following to core
```
mv langchain/langchain/utils/json_schema.py core/langchain_core/utils
mv langchain/langchain/utils/html.py core/langchain_core/utils
mv langchain/langchain/utils/strings.py core/langchain_core/utils
cat langchain/langchain/utils/env.py >> core/langchain_core/utils/env.py
rm langchain/langchain/utils/env.py
```

See .scripts/community_split/script_integrations.sh for all changes

docs/api_reference/create_api_rst.py

@@ -14,9 +14,10 @@ HERE = Path(__file__).parent
 PKG_DIR = ROOT_DIR / "libs" / "langchain" / "langchain"
 EXP_DIR = ROOT_DIR / "libs" / "experimental" / "langchain_experimental"
 CORE_DIR = ROOT_DIR / "libs" / "core" / "langchain_core"
+COMMUNITY_DIR = ROOT_DIR / "libs" / "core" / "langchain_community"
 WRITE_FILE = HERE / "api_reference.rst"
 EXP_WRITE_FILE = HERE / "experimental_api_reference.rst"
-CORE_WRITE_FILE = HERE / "core_api_reference.rst"
+COMMUNITY_WRITE_FILE = HERE / "community_api_reference.rst"
 
 
 ClassKind = Literal["TypedDict", "Regular", "Pydantic", "enum"]
@@ -302,6 +303,7 @@ package_namespace = {
     "langchain": "langchain",
     "experimental": "langchain_experimental",
     "core": "langchain_core",
+    "community": "langchain_community",
 }
 
 
@@ -316,6 +318,7 @@ def _out_file_path(package_name: str = "langchain") -> Path:
         "langchain": "",
         "experimental": "experimental_",
         "core": "core_",
+        "community": "community_",
     }
     return HERE / f"{name_prefix[package_name]}api_reference.rst"
 
@@ -326,6 +329,7 @@ def _doc_first_line(package_name: str = "langchain") -> str:
         "langchain": "",
         "experimental": "experimental",
         "core": "core",
+        "community": "community",
     }
     return f".. {prefix[package_name]}_api_reference:\n\n"
 
@@ -335,6 +339,7 @@ def main() -> None:
     _build_rst_file(package_name="core")
     _build_rst_file(package_name="langchain")
     _build_rst_file(package_name="experimental")
+    _build_rst_file(package_name="community")
 
 
 if __name__ == "__main__":

docs/api_reference/requirements.txt

@@ -1,6 +1,7 @@
--e libs/langchain
 -e libs/experimental
+-e libs/langchain
 -e libs/core
+-e libs/community
 pydantic<2
 autodoc_pydantic==1.8.0
 myst_parser

docs/api_reference/themes/scikit-learn-modern/nav.html

@@ -37,6 +37,9 @@
         <li class="nav-item">
           <a class="sk-nav-link nav-link" href="{{ pathto('core_api_reference') }}">Core</a>
         </li>
+        <li class="nav-item">
+          <a class="sk-nav-link nav-link" href="{{ pathto('community_api_reference') }}">Community</a>
+        </li>
         <li class="nav-item">
           <a class="sk-nav-link nav-link" href="{{ pathto('experimental_api_reference') }}">Experimental</a>
         </li>