Docusarus: Init Project

Summary:
This starts us transitioning the Yoga website off of an ancient version of Gatsby by initializing a new Docusaurus project. This commit adds a new stock project, to be filled in later, then fixes license lint errors.

Note that this seems to have init'd using npm, but in the next diff I convert this to yarn workspaces anyway.

Reviewed By: yungsters

Differential Revision: D46884434

fbshipit-source-id: ee388aa9388b1030dbbf59a73dd1529fee05065c

website-next/babel.config.js

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+module.exports = {
+  presets: [require.resolve('@docusaurus/core/lib/babel/preset')],
+};