Add expo to the existing react native project

[NigelBreslaw]

Right now the real mobile app does nothing. The first step requires iOS to be able to access the ASWebAuthenticationSession view. Even this can become a rabbit hole of new topics to learn such as creating a native module or the new turbo module.

As expo has a webview that can handle this. It claims to not take over the whole project (does not need ejecting later) and the size is minimal we will add in support now.