e633cc9c24
This: 1. Introduces a variable for the Course Outline view in Studio. A custom theme can override it to add new editors. 2. Exports a function for creating new editor modals. A custom theme can use it to create editors without adding boilerplate code. 3. Adds a pluggable override for XBlock fields that are passed to the Studio. Without this, custom editors in Studio cannot retrieve values of XBlock fields.