add config ALLOW_ADMIN_EMAIL_LOGIN and implement password-less SOGo login admins

data/web/mailbox.php

@@ -348,6 +348,11 @@ $is_dual = (!empty($_SESSION["dual-login"]["username"])) ? 'true' : 'false';
 echo "var role = '". $role . "';\n";
 echo "var is_dual = " . $is_dual . ";\n";
 echo "var pagination_size = '". $PAGINATION_SIZE . "';\n";
+$ALLOW_ADMIN_EMAIL_LOGIN = (preg_match(
+	"/^([yY][eE][sS]|[yY])+$/",
+    $_ENV["ALLOW_ADMIN_EMAIL_LOGIN"]
+)) ? "true" : "false";
+echo "var ALLOW_ADMIN_EMAIL_LOGIN = " . $ALLOW_ADMIN_EMAIL_LOGIN . ";\n";
 ?>
 </script>
 <?php