E-mail notifications

observe_email_ensure_handler/2: Add a handler for receiving e-mail notifications
observe_email_status/2: Email status notification, sent when the validity of an email recipient changes
observe_email_failed/2: Notify that we could NOT send an e-mail (there might be a bounce later...) The Context is the depickled z_email:send/2 context.
observe_email_received/2: Notification sent to a site when e-mail for that site is received
observe_email_add_handler/2: Add a handler for receiving e-mail notifications
observe_email_bounced/2: Bounced e-mail notification. The recipient is the e-mail that is bouncing. When the the message_nr is unknown the it is set to ‘undefined’. This can happen if…
observe_email_drop_handler/2: Drop an e-mail handler for a user/resource id. (notify). The notification, user and resource should be the same as when the handler was registered.
observe_email_is_blocked/2: Check if an email address is blocked
observe_email_sent/2: Notify that we could NOT send an e-mail (there might be a bounce later...) The Context is the depickled z_email:send/2 context.
observe_email_dkim_options/2: Return the options for the DKIM signature on outgoing emails. Called during email encoding.
observe_email_send_encoded/2: Add a handler for receiving e-mail notifications
observe_email_is_recipient_ok/2: Check if an email address is safe to send email to. The email address is not blocked and is not marked as bouncing.