feat: add necessary bits to rewrite sender and recipient for external relay

roles/smtprelay/templates/main.cf.j2

@@ -8,6 +8,13 @@ myorigin = {{ smtprelay_origin }}
 # Uncomment the next line to generate "delayed mail" warnings
 #delay_warning_time = 4h
 
+{% if smtprelay_origin not in ["mateu.be"] %}
+recipient_canonical_maps = regexp:/etc/postfix/recipient_canonical
+sender_canonical_classes = envelope_sender, header_sender
+sender_canonical_maps =  regexp:/etc/postfix/sender_canonical_maps
+smtp_header_checks = regexp:/etc/postfix/header_check
+{% endif %}
+
 alias_maps = hash:/etc/aliases
 alias_database = hash:/etc/aliases
 mydestination = $myhostname, localhost.$mydomain, localhost