Support multiple containers for pod logs

Problem to solve

In https://gitlab.com/gitlab-org/gitlab-ee/issues/12819, we discovered that the pod log feature doesn't work on pods with more than one container. As a short-term fix, we decided to show the first container by default. But, we should allow users to see all of the containers and to select which one they want to see the log for.

Intended users

Further details

Design proposal

After the user clicks through to a specific pod log from the environments page, they will now see a containers dropdown in addition to the environment and pod dropdowns:

Permissions and Security

Documentation

Testing

What does success look like, and how can we measure that?

What is the type of buyer?

Links / references