Imrove the way Feature is created.

[Jeevuz]

I think the usability of the library can be improved if you change

abstract class Feature {
    abstract val id: String
}

to

abstract class FeatureNew(internal val id: String)

So the users will be able to add features like this

object New : FeatureNew("Экран")

instead of this

object Old : Feature() {
    override val id: String = "Экран кэшбека. Отображать персональные предложения"
}