hook up the add new tag page

lib/pages/AddPage.dart

@@ -0,0 +1,38 @@
+import 'package:flutter/material.dart';
+import 'package:libac_dart/nbt/Tag.dart';
+import 'package:nbteditor/Constants.dart';
+
+class AddPage extends StatefulWidget {
+  @override
+  State<StatefulWidget> createState() => AddState();
+}
+
+class AddState extends State<AddPage> {
+  @override
+  void didChangeDependencies() {
+    var args = ModalRoute.of(context)!.settings.arguments as AddElementArgs;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text("Add Tag"),
+        backgroundColor: Constants.TITLEBAR_COLOR,
+      ),
+      body: Padding(
+        padding: EdgeInsets.all(8),
+        child: SingleChildScrollView(
+          child: Column(
+            children: [],
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+class AddElementArgs {
+  Tag tag;
+  AddElementArgs({required this.tag});
+}