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

libs/community/langchain_community/tools/file_management/utils.py

@@ -0,0 +1,54 @@
+import sys
+from pathlib import Path
+from typing import Optional
+
+from langchain_core.pydantic_v1 import BaseModel
+
+
+def is_relative_to(path: Path, root: Path) -> bool:
+    """Check if path is relative to root."""
+    if sys.version_info >= (3, 9):
+        # No need for a try/except block in Python 3.8+.
+        return path.is_relative_to(root)
+    try:
+        path.relative_to(root)
+        return True
+    except ValueError:
+        return False
+
+
+INVALID_PATH_TEMPLATE = (
+    "Error: Access denied to {arg_name}: {value}."
+    " Permission granted exclusively to the current working directory"
+)
+
+
+class FileValidationError(ValueError):
+    """Error for paths outside the root directory."""
+
+
+class BaseFileToolMixin(BaseModel):
+    """Mixin for file system tools."""
+
+    root_dir: Optional[str] = None
+    """The final path will be chosen relative to root_dir if specified."""
+
+    def get_relative_path(self, file_path: str) -> Path:
+        """Get the relative path, returning an error if unsupported."""
+        if self.root_dir is None:
+            return Path(file_path)
+        return get_validated_relative_path(Path(self.root_dir), file_path)
+
+
+def get_validated_relative_path(root: Path, user_path: str) -> Path:
+    """Resolve a relative path, raising an error if not within the root directory."""
+    # Note, this still permits symlinks from outside that point within the root.
+    # Further validation would be needed if those are to be disallowed.
+    root = root.resolve()
+    full_path = (root / user_path).resolve()
+
+    if not is_relative_to(full_path, root):
+        raise FileValidationError(
+            f"Path {user_path} is outside of the allowed directory {root}"
+        )
+    return full_path