I have removed the “idea” tag from this thread, because… we have an email service now!
It’s already handling email for a handful of accounts, mostly the main Kosmos ones, which we were using Gandi mailboxes for, plus a couple of normal user accounts for more testing. It’s already possible to choose between local delivery and remote forwarding by just changing the maildrop attribute in LDAP.
There’s an open WIP PR for the server configs (with some things not pushed yet). However, the akkounts part for generating/updating email passwords and LDAP attributes is still missing.
If someone wants to test it with their own accounts already, please DM me here, and I can manually add the LDAP attributes for you.