Explore adding a check for the GPT Data Generator

We need to add a check for the GPT Data Generator to ensure that it works before releasing the new version. This issue is to explore the best approach to do it keeping in mind that we can't run it against Staging.

Current proposal:

• Check job runs only when GPT_DATA_GENERATOR_VERSION is set
• Build docker image for the Generator, then spin up base GitLab performance image using run-gitlab-docker and run the Generator tool against it