feat(PasswordAuthentication): Registration and authentication with local credentials

[jimsynz]

This is missing a bunch of features that you probably want to use (eg confirmation, password resets), but it's a pretty good place to put a stake in the sand and say it works.

[zachdaniel]

This is 🔥 🔥 🔥

[zachdaniel]

Is subject_name really generic to all authentication? i.e some tokens might not use "subjects". I guess some kind of identifier is though.

[jimsynz]

Yeah, I couldn't think of a more generic term for the concept. Happy to take suggestions :)

[zachdaniel]

Unfortunately, doing this at compile time is a harder task than it would seem. This won't necessarily get all resources because of the registry/api split. The split between registries and APIs was necessary in order to prevent massive compile time blockages/deadlocks, but it also makes validations based on enumerating resources like this, sadly undeterministic. Partial recompiles can result in this module not recompiling and therefore it can be out of date. Other things solve for this by requiring the registry be explicitly stated, and using Registry.Info.entries/1: https://github.com/ash-project/ash_graphql/blob/main/documentation/tutorials/getting-started-with-graphql.md#add-ashgraphql-to-your-schema

Also happy to see some experimentation here around using things like Api.Info.registry(api) |> Code.ensure_compiled!() or Api.Info.registry(api).spark_dsl_config() to see if that causes the proper compile time dependency (from this module to the registry of all configured api module). If that works then I'd prefer to take that approach elsewhere also.