Merge branch '6249-confidential-issue' into 'develop'

Prevent unprivileged users from accessing or flushing the postfix mail queue

See merge request ispconfig-confidential/ispconfig3!6

install/tpl/debian_postfix.conf.master

@@ -59,3 +59,5 @@ smtp_sender_dependent_authentication = yes
 smtp_sasl_auth_enable = yes
 smtp_sasl_security_options = noanonymous, noplaintext
 smtp_sasl_tls_security_options = noanonymous
+authorized_flush_users =
+authorized_mailq_users = nagios, icinga

install/tpl/fedora_postfix.conf.master

@@ -55,3 +55,5 @@ smtp_sender_dependent_authentication = yes
 smtp_sasl_auth_enable = yes
 smtp_sasl_security_options = noanonymous, noplaintext
 smtp_sasl_tls_security_options = noanonymous
+authorized_flush_users =
+authorized_mailq_users = nagios, icinga

install/tpl/gentoo_postfix.conf.master

@@ -54,3 +54,5 @@ smtp_sender_dependent_authentication = yes
 smtp_sasl_auth_enable = yes
 smtp_sasl_security_options = noanonymous, noplaintext
 smtp_sasl_tls_security_options = noanonymous
+authorized_flush_users =
+authorized_mailq_users = nagios, icinga

install/tpl/opensuse_postfix.conf.master

@@ -57,3 +57,5 @@ smtp_sender_dependent_authentication = yes
 smtp_sasl_auth_enable = yes
 smtp_sasl_security_options = noanonymous, noplaintext
 smtp_sasl_tls_security_options = noanonymous
+authorized_flush_users =
+authorized_mailq_users = nagios, icinga