Add local SMTP relay conf

.config/opensmtpd/dest

@@ -0,0 +1 @@
+/etc/smtpd

.config/opensmtpd/smtpd.conf

@@ -0,0 +1,10 @@
+# This is the smtpd server system-wide configuration file.
+# See smtpd.conf(5) for more information.
+
+# To accept external mail, replace with: listen on all
+listen on localhost
+
+# If you edit the file, you have to run "smtpctl update table aliases"
+table aliases file:/etc/smtpd/aliases
+table secrets file:/etc/mail/secrets
+accept from local for any relay via smtps+auth://utc@smtps.utc.fr:465 auth <secrets> as "quentin.duchemin@hds.utc.fr"