Hardcoded paths in offline versions

Transferring from #313 (comment 231391024)

Premium customer found several hard-coded links to https://docs.gitlab.com in the offline, version-specific doc archives. This blocks access to version-specific documentation in a number of cases and breaks expected "offline" availability.

See attached file (11.11-hardcoded.txt) for a list of hardcoded links including the filename and line numbers in which they occur on version 11.11 of offline doc archives.

Here's the script we use for the links https://gitlab.com/gitlab-org/gitlab-docs/blob/master/scripts/normalize-links.sh. Once fixed, we'd need to backport this to all previous versions!