Replace screens in the tutorial fragment and screenshots for F-Droid
Summary:
Replace F-Droid screens for en
Replace F-Droid screens for it
Add missing images
Test Plan: Menu > "Show tutorial".
Reviewers: valerio.bozzolan
Reviewed By: valerio.bozzolan
Subscribers: valerio.bozzolan, Libre BusTO
Project Tags: Libre BusTO
Differential Revision: https://gitpull.it/D219
