[Feature suggestion] Add system role

[danielaki]

Thanks for the great work.

According to https://platform.openai.com/docs/guides/chat/introduction

openai.ChatCompletion.create(
  model="gpt-3.5-turbo",
  messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Who won the world series in 2020?"},
        {"role": "assistant", "content": "The Los Angeles Dodgers won the World Series in 2020."},
        {"role": "user", "content": "Where was it played?"}
    ]
)

Seen like we can specify a "system role" to apply on the assistant role? If that's so, maybe we can choose in the beginning of the chat to let user select a role for the assistant? Is it possible to configure it so that when opening the chat, it automatically enters a predefined model of the add system role?

Example: fastgpt.app/SystemRole1 fastgpt.app/SystemRole2 fastgpt.app/SystemRole3