lucifer: 
https://community.metabrainz.org/t/gsoc-2025-centralized-notification-system-for-metabrainz/751062/6

initally we’ll be using the send_mail function from brainzutil to send out mails directly, but later for musicbrainz integration, we’ll need to integrate MB-mail service to send out mails with MB- mail templates.

while the cron job is for sending out normal (plain text) mails for user’s with digest enabled ( it will check if digest age is reached, then it’ll send out the mail)