Docs: container images listing in architecture is out of date

Problem to solve

https://docs.gitlab.com/charts/architecture/architecture.html#docker-container-images

The Docker Container Images section of doc/architecture/architecture/ is out of date.

Further details

1. We now ship gitlab-org/container-registry vs upstream docker/distribution
2. Not present: KAS, Praefect, ...

Proposal

Revisit this content, ensuring that all indices are updated appropriately.

Who can address the issue

Any Distribution team member, or any party familiar with these charts and the images they consume.