Merge branch '493994-aqualls-last-illustration' into 'master'

Replace old diagram with editable illustration

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/183610



Merged-by: Russell Dickenson <rdickenson@gitlab.com>
Approved-by: Russell Dickenson <rdickenson@gitlab.com>
Co-authored-by: Amy Qualls <aqualls@gitlab.com>