Use stable docker image instead of latest

What does this MR do?

• Updates documentation to use docker:stable image instead of docker:latest.
• Updates all instances of docker:dind to docker:stable-dind.

There's no reason to use and advertise on latest for these images.

Are there points in the code the reviewer needs to double check?

Other places in the doc where docker:latest could be recommended. Other places in the doc where docker:dind could be recommended.

Why was this MR needed?

https://gitlab.com/gitlab-org/gitlab-ce/issues/45277#note_68088871

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Documentation created/updated

What are the relevant issue numbers?

• gitlab-org/gitlab-ce#45277