Page comments
Enable comment on specific pages like /service/email/mailbox_details/test@example.org/.
- Users and admins can write 0-1 comments each.
- (optional) comments have an option "cascading" which makes
/service/email/s comment visible at/service/email/mailbox_details/etc.
Open Questions
- Is this going to carnivora and if that's the case, is it a new schema?
- What about i18n?