[WIP] Add GitHub Action for releasing the auth app (mobile and desktop)

[mnvr]

Description

This action will take the latest auth code, build the iOS/Android apps, and create a draft release using it.

It will also then create a desktop build of auth. Since the desktop build is currently in beta, this might be neutered when we merge this into main for now.

Tests

This PR is the test. I'll be adding commits as I fill this in. These commits will create a test tag (that I'll also delete later).