tools/mmgotool: move into monorepo (#24010)

tools/mmgotool/main.go

@@ -0,0 +1,16 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package main
+
+import (
+	"os"
+
+	"github.com/mattermost/mattermost/tools/mmgotool/commands"
+)
+
+func main() {
+	if err := commands.Run(os.Args[1:]); err != nil {
+		os.Exit(1)
+	}
+}