Add native Apple and Google sign in for iOS and Android

[dshukertjr]

Feature request

Is your feature request related to a problem? Please describe.

Currently this package only support OAuth sign in via signInWithOAuth(). This opens up the web view, which is not ideal for native apps. Supabase currently supports native sign in for Google and Apple login, so it would be great if we can support them in this package.

Describe the solution you'd like

Add an easy way to implement Apple and Google native sign in.

Describe alternatives you've considered

Create an parameter on SupaSocialsAuth class that accepts Widget so that users can pass their own widget to be displayed. This would allow the users to add Native sign in button, but does not bring the convenience.

[FatumaA]

Seems the suggestion to add a widget is simple enough