In order to move InitialReduxStateResponse to lib, we need to move NavInfo to lib.
In order to move NavInfo to lib, we need to move NavigationTab, LoginMethod, NavigationSettingsSection`, and NavigationChatMode to `lib.
Because those types are web-specific, we should give them a Web* prefix in lib. This is the first diff that does that for NavigationTab. Would've prefered to give them all the types the Web* prefix in one diff, but will break it up for easier review.