Refactor welcome screens logic

[soosr]

These two PRs (#10881, #10878) highlighted perfectly that the welcome screen logic is overcomplicated and very fragile.
This issue is for not forgetting to clean it up.

The main source of the problem is Carousel control which provides the transition animation. Since we are planning to have a transition animation between every view, once that is done, the control can be removed and we can simplify it. Parking until then.

[yahiheb]

The two first dialogs are filled with text that doesn't add any value and many users will not read that anyway.

My very simply suggestion to improve the UX and to solve this issue is to remove those two first unneeded dialogs and to directly display the important one which is the fee dialog.

This would save us a lot of time and resources which could have been saved already when I have suggested the same over 7 months ago. #9534 (review)