[FEATURE] Stop prompting when pressing `q`

**Feature description**
As it is usually done in many CLI-Tools we want to allow the user to `quit` from the prompting.

The user should be able to press `q`, which interrupts the current prompt and returns a null value.

**Additional Information**
I am not sure if `None` is a possible return value to show that the process was interrupted. It may be better to throw a `KeyboardInterrupt`.
