refactor!: finish parser migration

Finally! :)

This removes all code related to the old parser.

#65

lib/parser/classes/MusicShelf.js

@@ -0,0 +1,29 @@
+'use strict';
+
+const Parser = require('..');
+const Text = require('./Text');
+const NavigationEndpoint = require('./NavigationEndpoint');
+
+class MusicShelf {
+  type = 'MusicShelf';
+
+  constructor(data) {
+    this.title = new Text(data.title).toString();
+
+    this.contents = Parser.parse(data.contents);
+
+    if (data.bottomEndpoint) {
+      this.endpoint = new NavigationEndpoint(data.bottomEndpoint);
+    }
+
+    if (data.continuations) {
+      this.continuation = data.continuations?.[0].nextContinuationData.continuation;
+    }
+
+    if (data.bottomText) {
+      this.bottom_text = new Text(data.bottomText);
+    }
+  }
+}
+
+module.exports = MusicShelf;