feat: configurable smtp

zeroconf.conf

@@ -1,5 +1,5 @@
 set mmonit http://@@MMONIT@@/collector
-set mailserver postfix port 25 using hostname @@HOSTNAME@@
+set mailserver @@POSTFIX@@ port 25 using hostname @@HOSTNAME@@
 
 set alert @@EMAIL@@
 

zeroconf.sh

@@ -13,6 +13,7 @@ sed -re "s/@@EMAIL@@/${EMAIL}/" \
      -e "s/@@HOSTNAME@@/${EMAIL_FROM#*@}/" \
      -e "s/@@MMONIT@@/${MMONIT}/" \
      -e "s/@@CREDENTIALS@@/${CREDENTIALS}/" \
+     -e "s/@@POSTFIX@@/${POSTFIX:-postfix}/" \
      /etc/zeroconf.conf > /etc/monit.d/zeroconf.conf
 
 monit -t