Set a PIN after manual backup flow (align to iOS)

- User is reminded to do a backup in several places (in Home when they have a balance, in Receive, in Buy, in Security tab)
- When they start this flow they are asked to take note of their recovery phrase and than verify some words
- We also force them to set a PIN which is more portable than faceID in case they lose their phone
- This last step already happens in iOS, not in Android