twitchAuthCodeRouter has hardcoded port 3000

[mjfwebb]

The twitchAuthCodeRouter should respect the port configured in config.json, but at the moment it is hard coded to use port 3000.

https://github.com/mjfwebb/twitch-bot/blob/bfc66b4cb5a9542e04554e5fd9eeb4a508cecb08/server/src/auth/twitch.ts#L195