feat(sdbapi): simplify verifying if a user exists

WIP(sdbapi): game creation API

feat(sdbapi): helper for getting user by email

feat!(sdbapi): change errors to apierror

WIP(sdbapi): game info API endpoint

Change how user details are fetched

/token will now return the user ID as well

Return user email from register

Add a temporary version number to the API

Basic API with register and login (#1)

Reviewed-on: https://src.quest/skye/deck-builder/pulls/1