As a teacher
I want to be able to highlight and remove highlight sections and see the change applied in the course index
so I don't need to reload the page to confirm the changes were properly applied.

Acceptance criteria:

For Topic core format:

1. Highlighted section is styled differently in the course index
2.  Highlighted section is synchronized between Course index and course main content area.
3. When section is highlighted in the course main content area is also marked as highlighted in the course index.
4. When highlight is removed for a section in the course main content area is not  marked as highlighted in the course index anymore.