community[minor]: Add iFlyTek Spark LLM chat model support (#13389)

- **Description:** This PR enables LangChain to access the iFlyTek's
Spark LLM via the chat_models wrapper.
  - **Dependencies:** websocket-client ^1.6.1
  - **Tag maintainer:** @baskaryan 

### SparkLLM chat model usage

Get SparkLLM's app_id, api_key and api_secret from [iFlyTek SparkLLM API
Console](https://console.xfyun.cn/services/bm3) (for more info, see
[iFlyTek SparkLLM Intro](https://xinghuo.xfyun.cn/sparkapi) ), then set
environment variables `IFLYTEK_SPARK_APP_ID`, `IFLYTEK_SPARK_API_KEY`
and `IFLYTEK_SPARK_API_SECRET` or pass parameters when using it like the
demo below:

```python3
from langchain.chat_models.sparkllm import ChatSparkLLM

client = ChatSparkLLM(
    spark_app_id="<app_id>",
    spark_api_key="<api_key>",
    spark_api_secret="<api_secret>"
)
```

docs/docs/integrations/chat/sparkllm.ipynb

@@ -0,0 +1,99 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "3ddface67cd10a87",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "# SparkLLM Chat\n",
+    "\n",
+    "SparkLLM chat models API by iFlyTek. For more information, see [iFlyTek Open Platform](https://www.xfyun.cn/)."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Basic use"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "43daa39972d4c533",
+   "metadata": {
+    "collapsed": false,
+    "is_executing": true
+   },
+   "outputs": [],
+   "source": [
+    "\"\"\"For basic init and call\"\"\"\n",
+    "from langchain.chat_models import ChatSparkLLM\n",
+    "from langchain.schema import HumanMessage\n",
+    "\n",
+    "chat = ChatSparkLLM(\n",
+    "    spark_app_id=\"<app_id>\", spark_api_key=\"<api_key>\", spark_api_secret=\"<api_secret>\"\n",
+    ")\n",
+    "message = HumanMessage(content=\"Hello\")\n",
+    "chat([message])"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "df755f4c5689510",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "- Get SparkLLM's app_id, api_key and api_secret from [iFlyTek SparkLLM API Console](https://console.xfyun.cn/services/bm3) (for more info, see [iFlyTek SparkLLM Intro](https://xinghuo.xfyun.cn/sparkapi) ), then set environment variables `IFLYTEK_SPARK_APP_ID`, `IFLYTEK_SPARK_API_KEY` and `IFLYTEK_SPARK_API_SECRET` or pass parameters when creating `ChatSparkLLM` as the demo above."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "984e32ee47bc6772",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "## For ChatSparkLLM with Streaming"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7dc162bd65fec08f",
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "chat = ChatSparkLLM(streaming=True)\n",
+    "for chunk in chat.stream(\"Hello!\"):\n",
+    "    print(chunk.content, end=\"\")"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.6"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}