refactor!: finish parser migration

Finally! :)

This removes all code related to the old parser.

#65

lib/parser/classes/menus/SimpleMenuHeader.js

@@ -0,0 +1,15 @@
+'use strict';
+
+const Parser = require('../..');
+const Text = require('../Text');
+
+class SimpleMenuHeader {
+  type = 'SimpleMenuHeader';
+
+  constructor(data) {
+    this.title = new Text(data.title);
+    this.buttons = Parser.parse(data.buttons);
+  }
+}
+
+module.exports = SimpleMenuHeader;