Perssist refresh tokens on reboot

[coolapso]

A new User authentication token must be generated every time the application reboots, while this is not a problem when using application tokens, this becomes a problem when using user tokens in environments where containers often restart, forcing users to manually authorize the application again to issue a new user and refresh token.

Should find a safe way to store both the user access token and the refresh token and persist them through reboots

[coolapso]

In the meantime a work around is to pre-generate the tokens with twich CLI and provide them as env variable / flag:

https://github.com/coolapso/prometheus-twitch-exporter?tab=readme-ov-file#pre-generated-access-token