Re-create backend link tracking information when a course is imported or rerun

[bradenmacdonald]

As an author, when I export a course that has library-linked content (including components, units, subsections, or sections) and then import it - either under the same course ID or a new course ID - I expect the "library updates" page to continue working as before, and show pending updates from the library.

As an author, when I create a new run of a course that has library-linked content, I expect the "library updates" page to continue working as it did in the previous run, and show pending updates from the library.

[ChrisChV]

Hi @jmakowski1123 @sdaitzman @edschema This issue is ready for AC testing on the sandbox