expose custom logger

[taylorchu]

In canal, the log output is not structured.

In #167, the idea of custom logger is briefly discussed. We would like to use logger from logrus for example to be able to post-process structured logs easily.

[siddontang]

Yes, @taylorchu

Can you send me a PR? Maybe we can pass the logrus Logger to go-mysql. if not set, we can use the default standard logger.

[dveeden]

With #993 merged I think we should probably also close this now that we use log/slog.

@serprex @lance6716 do you agree?

[lance6716]

I agree that we can close this issue. Please refer to the Logging section in README