Configure event notification sender email address

This commit adds the ability to configure the email address used as
sender, CC, and reply-to in event notification emails via the
<location/event_sender_email> configuration entry."

website/agenda/config/config.cgi.off

@@ -72,6 +72,7 @@ domain                      ${DOMAIN}
     # multi language support
     admin_pot_dir           ${BASE_DIR}/agenda/planung/pot/
     email                   info@${DOMAIN}
+    event_sender_email      programm@${DOMAIN}
     theme                   default
 </locations>
 

website/agenda/planung/notify-events.cgi

@@ -202,12 +202,12 @@ sub getMail {
         $event->{noRecipient} = 1;
         return;
     }
-
+    my $sender = $config->{location}->{event_sender_email};
     my $mail = {
-        'From'     => 'programm@radiopiloten.de',
+        'From'     => $sender,
         'To'       => join( ', ', @$userMails ),
-        'Cc'       => 'programm@radiopiloten.de',
-        'Reply-To' => 'programm@radiopiloten.de',
+        'Cc'       => $sender,
+        'Reply-To' => $sender,
         'Subject'  => "$event->{start} - $event->{full_title}",
         'Data'     => "Hallo " . join( ' und ', @$userNames ) . ",\n\n"
     };