Add a progress indicator to the walkthroughs to give  the user how many steps are left.

To improve the walkthrough UX, we can consider to add some type of progress indicator to show them how many steps are left. It can be some dot indicators on top that indicates what steps of the process they are at:
https://pub.dev/packages/smooth_page_indicator

or maybe some other type of step tracker
https://pub.dev/packages/step_progress_indicator
