fix: add old pages with link to new documentation

[KristinAoki]

Many partners have the pages checkbox and multiple choice pages bookmarked because they frequently reference those pages. However, those pages were renamed and moved to new urls (/single_select and /multi_select), so the form links lead to dead pages. This PR adds the pages back and offers a link to the corresponding new page.

Reviewers

Possible roles follow. The PR submitter checks the boxes after each reviewer finishes and gives :+1:.

• [x] Subject matter expert: @openedx/teaching-and-learning
• [ ] Partner support: @mondiaz

FYI: Tag anyone else who might be interested in this PR here.

Testing

• [ ] Ran ./run_tests.sh without warnings or errors

Post-review

• [ ] Add a comment with the description of this change or link this PR to the next release notes task.
• [ ] Squash commits