Move getInputInformation from xas_input to XASObjectDialog

Reminder: xas_input holds XASObjectWindow which holds XASObjectDialog.

By pushing getInputInforation down in the hierarchy of widgets, we can remove some layers of getters/setters.

Also, I plan to use it to build the XASObject so it makes sense to put it in the widget that actually hold the method buildXASObject.

I did it in two steps so the commits can be reviewed separately.