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/tests/integration_tests/llms/test_llamacpp.py

@@ -0,0 +1,88 @@
+# flake8: noqa
+"""Test Llama.cpp wrapper."""
+import os
+from typing import Generator
+from urllib.request import urlretrieve
+
+import pytest
+
+from langchain_community.llms import LlamaCpp
+
+from tests.unit_tests.callbacks.fake_callback_handler import FakeCallbackHandler
+
+
+def get_model() -> str:
+    """Download model. f
+    From https://huggingface.co/Sosaka/Alpaca-native-4bit-ggml/,
+    convert to new ggml format and return model path."""
+    model_url = "https://huggingface.co/Sosaka/Alpaca-native-4bit-ggml/resolve/main/ggml-alpaca-7b-q4.bin"
+    tokenizer_url = "https://huggingface.co/decapoda-research/llama-7b-hf/resolve/main/tokenizer.model"
+    conversion_script = "https://github.com/ggerganov/llama.cpp/raw/master/convert-unversioned-ggml-to-ggml.py"
+    local_filename = model_url.split("/")[-1]
+
+    if not os.path.exists("convert-unversioned-ggml-to-ggml.py"):
+        urlretrieve(conversion_script, "convert-unversioned-ggml-to-ggml.py")
+    if not os.path.exists("tokenizer.model"):
+        urlretrieve(tokenizer_url, "tokenizer.model")
+    if not os.path.exists(local_filename):
+        urlretrieve(model_url, local_filename)
+        os.system(f"python convert-unversioned-ggml-to-ggml.py . tokenizer.model")
+
+    return local_filename
+
+
+def test_llamacpp_inference() -> None:
+    """Test valid llama.cpp inference."""
+    model_path = get_model()
+    llm = LlamaCpp(model_path=model_path)
+    output = llm("Say foo:")
+    assert isinstance(output, str)
+    assert len(output) > 1
+
+
+def test_llamacpp_streaming() -> None:
+    """Test streaming tokens from LlamaCpp."""
+    model_path = get_model()
+    llm = LlamaCpp(model_path=model_path, max_tokens=10)
+    generator = llm.stream("Q: How do you say 'hello' in German? A:'", stop=["'"])
+    stream_results_string = ""
+    assert isinstance(generator, Generator)
+
+    for chunk in generator:
+        assert not isinstance(chunk, str)
+        # Note that this matches the OpenAI format:
+        assert isinstance(chunk["choices"][0]["text"], str)
+        stream_results_string += chunk["choices"][0]["text"]
+    assert len(stream_results_string.strip()) > 1
+
+
+def test_llamacpp_streaming_callback() -> None:
+    """Test that streaming correctly invokes on_llm_new_token callback."""
+    MAX_TOKENS = 5
+    OFF_BY_ONE = 1  # There may be an off by one error in the upstream code!
+
+    callback_handler = FakeCallbackHandler()
+    llm = LlamaCpp(
+        model_path=get_model(),
+        callbacks=[callback_handler],
+        verbose=True,
+        max_tokens=MAX_TOKENS,
+    )
+    llm("Q: Can you count to 10? A:'1, ")
+    assert callback_handler.llm_streams <= MAX_TOKENS + OFF_BY_ONE
+
+
+def test_llamacpp_model_kwargs() -> None:
+    llm = LlamaCpp(model_path=get_model(), model_kwargs={"n_gqa": None})
+    assert llm.model_kwargs == {"n_gqa": None}
+
+
+def test_llamacpp_invalid_model_kwargs() -> None:
+    with pytest.raises(ValueError):
+        LlamaCpp(model_path=get_model(), model_kwargs={"n_ctx": 1024})
+
+
+def test_llamacpp_incorrect_field() -> None:
+    with pytest.warns(match="not default parameter"):
+        llm = LlamaCpp(model_path=get_model(), n_gqa=None)
+    llm.model_kwargs == {"n_gqa": None}