CP-CLI: Custom Cluster Pipeline CLI commands

[sj-williams]

Background

The Concourse custom cluster commands are really useful for spinning up custom test clusters and executing ginkgo tests against test clusters, but currently is fairly manual via fly and Concourse UI.

Create a CLI command for building and testing custom test clusters.

Do the same for running integration tests, and should we look at moving custom int tests into the test jobs pipeline too?

We could also do with having a look at allowing concurrent builds to run in this pipeline as currently they interrupt one another.

https://github.com/ministryofjustice/cloud-platform-terraform-concourse/blob/main/pipelines/manager/main/custom-cluster.yaml

Definition of done

• [ ] readme has been updated
• [ ] user docs have been updated
• [ ] another team member has reviewed
• [ ] prepare demo for the team

Reference

How to write good user stories