Added a new `Varaible` and `Validator` to be able to ask for the project folder
Removed default value for `directory` so we can check if the user specifically set it or not.
Removed `setDirectory()` because what it's `TODO` suggested was already implemented some time ago
We now skip the questions for ant and eclipse files if we detect that a project already exists in the target location
We now ask for the project folder on the console if it wasn't passed as an argument
Extracted all useful code from `HelloWorld` into a base class and added `Simple` and `JavaInterop` projects