openai[minor]: implement langchain-openai package (#15503)

Todo

- [x] copy over integration tests
- [x] update docs with new instructions in #15513 
- [x] add linear ticket to bump core -> community, community->langchain,
and core->openai deps
- [ ] (optional): add `pip install langchain-openai` command to each
notebook using it
- [x] Update docstrings to not need `openai` install
- [x] Add serialization
- [x] deprecate old models

Contributor steps:

- [x] Add secret names to manual integrations workflow in
.github/workflows/_integration_test.yml
- [x] Add secrets to release workflow (for pre-release testing) in
.github/workflows/_release.yml

Maintainer steps (Contributors should not do these):

- [x] set up pypi and test pypi projects
- [x] add credential secrets to Github Actions
- [ ] add package to conda-forge


Functional changes to existing classes:

- now relies on openai client v1 (1.6.1) via concrete dep in
langchain-openai package

Codebase organization

- some function calling stuff moved to
`langchain_core.utils.function_calling` in order to be used in both
community and langchain-openai

libs/community/langchain_community/embeddings/azure_openai.py

@@ -5,6 +5,7 @@ import os
 import warnings
 from typing import Callable, Dict, Optional, Union
 
+from langchain_core._api.deprecation import deprecated
 from langchain_core.pydantic_v1 import Field, root_validator
 from langchain_core.utils import get_from_dict_or_env
 
@@ -12,6 +13,9 @@ from langchain_community.embeddings.openai import OpenAIEmbeddings
 from langchain_community.utils.openai import is_openai_v1
 
 
+@deprecated(
+    since="0.1.0", removal="0.2.0", alternative="langchain_openai.AzureOpenAIEmbeddings"
+)
 class AzureOpenAIEmbeddings(OpenAIEmbeddings):
     """`Azure OpenAI` Embeddings API."""