EM-494 Production pipeline setup

[dlzhry2nhs]

Summary

New Feature

Following on from the first-time into prod meeting, we can now merge this. The tests in the pipeline will fail, but the environment will still build, as and when we decide to release to prod.

I'll create a ticket to do the prod release and to create a prod test app so the tests will succeed going forward. Note: this PR just creates the Prod step. Manual approval is required and an RFC before we can actually release.

See comment below. Come and have a go if you think you're hard enough to fix the tests. I gave it a go but was not up to the job.

Reviews Required

• Dev

Review Checklist

ℹ️ This section is to be filled in by the reviewer.

• I have reviewed the changes in this PR and they fill all or part of the acceptance criteria of the ticket, and the code is in a mergeable state.
• If there were infrastructure, operational, or build changes, I have made sure there is sufficient evidence that the changes will work.
• I have ensured the changelog has been updated by the submitter, if necessary.