提供指定http.Server的ErrorLog功能

[Jardaliao]

What would you like to be added:
提供指定http.Server的ErrorLog功能

Why is this needed:
http.Server的错误日志默认会写到标准输出，但它提供了指定自定义Logger的口子，getty似乎没有开放这个口子？

http\server.go

type Server struct {
        // ErrorLog specifies an optional logger for errors accepting
	// connections, unexpected behavior from handlers, and
	// underlying FileSystem errors.
	// If nil, logging is done via the log package's standard logger.
	ErrorLog *log.Logger
}

getty\options.go

type ServerOptions struct {
	addr string
	// tls
	sslEnabled       bool
	tlsConfigBuilder TlsConfigBuilder
	// websocket
	path       string
	cert       string
	privateKey string
	caCert     string
	// task queue
	tPool gxsync.GenericTaskPool
}

[AlexStocks]

如上图，可以对你用的 logger 封装下，然后调用  SetLogger 这个接口函数即可