Add auth to topics page

When fixing a conflict in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10608, forgot to add this back. Also fixes broken links :/

added 3 commits

• 9486021b - add line to the end of the file
• b95989c6 - fix ee links
• bea64d42 - fix broken link

Compare with previous version

mentioned in merge request !10299 (closed)

I know we'll not use the topics page anymore, but this is an inoffensive change. I need it to fix the links in the authentication index (wherever we want to put it), and I don't want to struggle with the builds just to remove a link from the topics page.

merged

changed milestone to %9.1

mentioned in commit fe36a9c8

added ~149423 label

Picked into 9-1-stable, will go into 9.1.0-rc2

mentioned in commit 03dfbe24

mentioned in merge request !11045 (merged)