Request for re-design for Config class

[ryukato]

Need to think about that keep Config object is mutable. Since Config object contains configuration which is used during test run, so if a value of an attribute of Config object instance may cause something bad or un-expected result. I guess using builder pattern to build this Config object and making Config object immutable is better.

Any better idea is welcome.

[JiseongKim]

Okay, it looks good. If you prepare PR, let's review it together.