feat: support change log level at runtime

[lingsamuel]

Useful when:

1. check installation status with DEBUG log level, then change to WARN/ERROR
2. convenient to adjust the log level to analyze the runtime error

[ronething]

@lingsamuel maybe i can try this, can you assign it to me, thanks.

[ps-19]

Can we use Logrus?

package log

import (
    "os"
    "github.com/sirupsen/logrus"
)

var logger *logrus.Logger

func Configure() {
    logger = logrus.New()
    logger.SetLevel(logrus.DebugLevel)
}

func SetLogLevel(level logrus.Level) {
    logger.SetLevel(level)
}