Add a job to verify the Docker images appear on `hub.docker.com`

What does this MR do and why?

As part of the monthly release tasks, we create docker hub images as part of the release pipeline. The images appear on hub.docker.com shortly after the release manager runs the publish command. We need a way to automatically verify these images appear on hub.docker.com

Thus, this class uses the docker_hub_client we implemented in gitlab-com/gl-infra/delivery#20295 (closed) and addresses: gitlab-com/gl-infra/delivery#20194 (closed)

Content

• Add class to check for docker images tags
• Add specs

Testing

Pipeline

With no tags

• https://ops.gitlab.net/gitlab-org/release/tools/-/pipelines/3451505

With tags

• https://ops.gitlab.net/gitlab-org/release/tools/-/pipelines/3451528

Jobs

Erroring job

• https://ops.gitlab.net/gitlab-org/release/tools/-/jobs/14464938

Successful job

• https://ops.gitlab.net/gitlab-org/release/tools/-/jobs/14464968

Slack message

Error

• 

Success

• 

• https://gitlab.slack.com/archives/C047XHV7PQQ/p1719570485472499