This includes things like changing the post type name, etc.

Slightly related: #2.

QA testing instructions

1. Verify that creating, saving, and viewing stories works with the AMP plugin inactive
2. Verify that creating, saving, and viewing stories works with the AMP plugin active, but the stories experience disabled
3. When activating the stories experience, both "Stories" options should be visible in the admin menu
4. Verify that creating, saving, and viewing stories works with the AMP plugin active, and the stories experience enabled