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/utilities/python.py

@@ -0,0 +1,71 @@
+import functools
+import logging
+import multiprocessing
+import sys
+from io import StringIO
+from typing import Dict, Optional
+
+from langchain_core.pydantic_v1 import BaseModel, Field
+
+logger = logging.getLogger(__name__)
+
+
+@functools.lru_cache(maxsize=None)
+def warn_once() -> None:
+    """Warn once about the dangers of PythonREPL."""
+    logger.warning("Python REPL can execute arbitrary code. Use with caution.")
+
+
+class PythonREPL(BaseModel):
+    """Simulates a standalone Python REPL."""
+
+    globals: Optional[Dict] = Field(default_factory=dict, alias="_globals")
+    locals: Optional[Dict] = Field(default_factory=dict, alias="_locals")
+
+    @classmethod
+    def worker(
+        cls,
+        command: str,
+        globals: Optional[Dict],
+        locals: Optional[Dict],
+        queue: multiprocessing.Queue,
+    ) -> None:
+        old_stdout = sys.stdout
+        sys.stdout = mystdout = StringIO()
+        try:
+            exec(command, globals, locals)
+            sys.stdout = old_stdout
+            queue.put(mystdout.getvalue())
+        except Exception as e:
+            sys.stdout = old_stdout
+            queue.put(repr(e))
+
+    def run(self, command: str, timeout: Optional[int] = None) -> str:
+        """Run command with own globals/locals and returns anything printed.
+        Timeout after the specified number of seconds."""
+
+        # Warn against dangers of PythonREPL
+        warn_once()
+
+        queue: multiprocessing.Queue = multiprocessing.Queue()
+
+        # Only use multiprocessing if we are enforcing a timeout
+        if timeout is not None:
+            # create a Process
+            p = multiprocessing.Process(
+                target=self.worker, args=(command, self.globals, self.locals, queue)
+            )
+
+            # start it
+            p.start()
+
+            # wait for the process to finish or kill it after timeout seconds
+            p.join(timeout)
+
+            if p.is_alive():
+                p.terminate()
+                return "Execution timed out"
+        else:
+            self.worker(command, self.globals, self.locals, queue)
+        # get the result from the worker function
+        return queue.get()