feat(model): Support DeepSeek proxy LLM

[fangyinc]

Description

Support Deepseek proxy LLM

Closes #1490

How Has This Been Tested?

1. Use deepseek in DB-GPT
   Modify your .env

LLM_MODEL=deepseek_proxyllm
DEEPSEEK_MODEL_VERSION=deepseek-chat
DEEPSEEK_API_BASE=https://api.deepseek.com/v1
DEEPSEEK_API_KEY={your-deepseek-api-key}

Then restart DB-GPT to use it in the web page.

2. Use DeepseekLLMClient in python code.
   Create python file test_proxyllm.py

import asyncio
from dbgpt.core import ModelRequest
from dbgpt.model.proxy import DeepseekLLMClient
# You should set DEEPSEEK_API_KEY to your environment variables
client = DeepseekLLMClient()
print(asyncio.run(client.generate(ModelRequest._build("deepseek-chat", "你是谁？"))))

Run test_proxyllm.py

DEEPSEEK_API_KEY={your-deepseek-api-key} python test_proxyllm.py

The output like this:

ModelOutput(text=' 我是DeepSeek Chat，一个基于人工智能技术的虚拟助手，旨在通过对话交流为您提供信息查询、建议、解答问题等服务。我的目标是帮助用户更好地获取所需知识，解决问题，并提供一个便捷的互动体验。', error_code=0, incremental=False, model_context=None, finish_reason=None, usage={'completion_tokens': 47, 'prompt_tokens': 11, 'total_tokens': 58}, metrics=None)

Snapshots:

Include snapshots for easier review.

Checklist:

• My code follows the style guidelines of this project
• I have already rebased the commits and make the commit message conform to the project standard.
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• Any dependent changes have been merged and published in downstream modules

[csunny]

r+

[Aries-ckt]

r+