Merge branch 'ah-offset-optimization-docs' into 'master'

Add offset pagination optimization docs

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/157138



Merged-by: Tiger Watson <twatson@gitlab.com>
Approved-by: Tiger Watson <twatson@gitlab.com>
Reviewed-by: Tiger Watson <twatson@gitlab.com>
Reviewed-by: Abdul Wadood <awadood@gitlab.com>
Co-authored-by: Adam Hegyi <ahegyi@gitlab.com>