Moved coroutine usage in the ViewModels

[angelomarzocchi]

Updated Gradle clean task to make it compatible with new Gradle version.
I also moved couroutine usage in the ViewModel for 2 reasons:

1. it better follows the single responability principle: I don't see why calling a coroutine is a responsability of the UI.
2. The problem of the update cancelled when recomposition is being performed is not an issue anymore :)