Remove ES6 from the setup options, make it default to every project

[luboskmetko]

No description provided.

[jakub300]

This was discussed during eslint/prettier implementation, I think @arturkot had some arguments against this, Artur?

[luboskmetko]

Here I was just looking for ways to simplify setup, but if there are some issues with it, we can keep it as an option.

[arturkot]

@jakub300 I discussed it with @luboskmetko and agreed we should do it. FYI – personally I think it's a good update. We'll just make the project less accessible for less experienced devs.