Create page redirects for imported content

[brylie]

Since our URL structure on the new site will differ from the old Drupal site, we must create redirects for old URLs. That way, we preserve inbound links by redirecting to the same content at the new location.

Task

• add path to export data on Drupal site
• update import scripts to create a redirect for each imported item, when the path would differ

References

• https://docs.wagtail.org/en/stable/reference/contrib/redirects.html

[brylie]

I've gone through the content importers and added redirects wherever we used drupal_node_id in #725