Enhance - More messages::add updates (#2662)

convert more messages over to messsagse::add

app/fifo/fifo_add.php

@@ -276,7 +276,7 @@ if (count($_POST)>0 && strlen($_POST["persistformvar"]) == 0) {
 		$cache->delete("dialplan:".$_SESSION["context"]);
 
 	//redirect the user
-		$_SESSION["message"] = $text['message-add'];
+		messages::add($text['message-add']);
 		header("Location: ".PROJECT_PATH."/app/dialplan/dialplans.php?app_uuid=16589224-c876-aeb3-f59f-523a1c0801f7");
 		return;