Update email blacklist
schema.sql: Add missing table
Use internal anon auth for sending notifications
Use GraphQL to send audit event emails
metasrht-daily: use GraphQL to send emails

This moves all its email (and encryption key) handling from Python into
the Go API.
Use GQL endpoint to send password reset link
Adapt to GQL API change for sending test email
api: make sendEmailNotification recipient explicit

Having sendEmailNotification take a full message as argument is very
powerful, but restricting it to only send mail to the currently
logged-in user will in fact not get us very far. Examples of mails that
should be sent (potentially encrypted) that are not triggered by a
logged-in user include the password reset email, billing emails
triggered by metasrht-daily, and possibly more in other services.

This commit extends the API to include the username of the desired
recipient. This will not add much overhead to the callers and more
importantly, still make sure to keep any PGP-related code in meta.sr.ht.
Update blacklist
API: update email blacklist
Fix additional issue with admin-initiated deletion
Fix oversight with admin user deletion
Implement self-service account deletion
Schema: fix more missing cascades
API: update core-go
api: remove erroneous replace directive
Implement admin UI for user account deletion
API: Implement user account deletion
schema.sql: Add cascades for user deletion
schema.sql: Rename SQL indexes to PostgreSQL-style

References: https://todo.sr.ht/~sircmpwn/sr.ht/306