Need a better jwt mechanism to encrypt the content.

[chhsiao1981]

Provide the github link(s) of the file#line (請提供 github 關於 code 的 link)

https://github.com/Ptt-official-app/go-pttbbs/blob/main/api/auth_utils.go#L53

What would you like to discuss (你想要討論什麼呢？～)

Currently we are using jwt implemented by square.
https://github.com/Ptt-official-app/go-pttbbs/blob/main/go.mod#L16

However, currently the settings is only for verification.
The content of the access-token is not encrypted and can be viewed in https://jwt.io
This is not good in production.

We would like to have a better setting of jwt-token
to encrypt the content in the token as well.

It's with high probability that it's doable by just changing the setting of the square library.