Use default preset instead of having the user creating a presets

[bekicot]

With default presets automatically activated (see https://github.com/bbatsov/rubocop/blob/master/config/enabled.yml), giving the possibility the script to run without making additional configuration files.

[wisn]

Sure! I've planned this as well. Hanum will have a directory named presets which store every contributed presets. Suppose that I've created a presets for checking the OSM attributes data type. I will store it in presets directory. Then, I will update the configuration of Hanum. Well, I still thinking which way is the best to do that. Let see in this first Hanum release. 👍