ENYO-1020: refactor FileChooser to be a filePicker or a folderPicker

- Still used by ProjectWizard (folderPicker)
- Ready to be used by Phobos#saveAs (filePicker)

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>