Add fastapi server

[Undertone0809]

🚀 Feature Request

Add a fastapi server to expose API service.

SDK Usage:

from ecjtu import ECJTU

client = ECJTU(...)
client.start_api_server(port=8080)

Command Usage:

ecjtu server --stud_id xx --pwd xx --port 8080

[github-actions]

Hello @Undertone0809, thanks for your first issue and interest in our work 😊!

If this is a bug report, please provide screenshots, relevant logs and minimum viable code to reproduce your issue, which will help us debug the problem.

[Undertone0809]

ref: #46 #61