Convert codeowners custom extension to a helper
Why is this change being made?
Closes #8923 (closed)
As a preparation step for a Frontman migration, we want to convert all custom extensions to helpers, because Frontman does not support extensions.
Performance test results
NEW: bundle exec middleman build 983.12s user 35.76s system 992% cpu 1:42.65 total
OLD: bundle exec middleman build 993.31s user 35.91s system 960% cpu 1:47.12 total
Test link
https://8923-convert-codeowners-to-helper.about.gitlab-review.app/handbook/index.html
Edited by Vasilii Iakliushin