add support for mobile auth support via endpoint /auth/mobile

Problem

I'm currently working on a mobile app client for myself for iOS utilizing swift I got the frontend done I just need the auth to Accept a redirect parameter After login, redirects to the users 3rd party client of the users choosing

Proposed solution

I'm thinking of a solution if the user indicates when they are logging in that they are using a 3rd party the client then we could redirect back to the app client with the user signed in