Support user/password in backend

[tyler-dane]

Priority

High (would significantly improve my experience)

Feature Description

Support user/password sign-ups on the backend.

Use Case

This'll allow users to create an account using just a username (email) and password, which will make it easier to use Compass. It'll also allow them to sign in with their email/password on other devices or when their session expires.

Additionally, it makes it easier to self-host compass by decoupling the user from their google account.

Additional Context

No response