Merge branch 'docs-ra-expand-component-descriptions' into 'master'

Expand GitLab component descriptions in Reference Architecture pages

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/167445



Merged-by: Brendan Lynch <blynch@gitlab.com>
Approved-by: Grant Young <gyoung@gitlab.com>
Approved-by: Brendan Lynch <blynch@gitlab.com>
Reviewed-by: Brendan Lynch <blynch@gitlab.com>
Co-authored-by: Nailia Iskhakova <niskhakova@gitlab.com>