Optional deployment steps in Jenkinsfile

[kierenevans]

There's a pattern emerging regarding the ability to optionally promote a commit to different environments.

This pattern requires quite extensive Jenkinsfile changes to not choose an agent at first, run the build/test/publish on a my127ws agent, and then have a question regarding commit promotion pop up running on no agent.

It would be good to have this as a feature of the harness.

Apologies for vagueness, will try to flesh this out over time :)