VED-981 Add base infrastructure for the MNS Publisher feature

[dlzhry2nhs]

Summary

• Routine Change

Simple architecture change to enable coding work to begin on the Lambda. Details of the ticket are no longer relevant, so will update in JIRA. Discussed with architect who was happy with the changes.

• Adds a stream to the delta table
• Adds a new MNS Publisher Lambda function which will read from the new delta stream

This approach minimises the number of new components we will need while ensuring that we are only publishing MNS events where the event was successfully persisted across the whole system i.e. the events table and delta.

Have raised a couple of questions, which I'm happy to look into under this PR or

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 of the acceptance criteria of the ticket.
• If there were infrastructure, operational, or build changes, I have made sure there is sufficient evidence that the changes will work.
• If there were changes that are outside of the regular release processes e.g. account infrastructure to setup, manual setup for external API integrations, secrets to set, then I have checked that the developer has flagged this to the Tech Lead as release steps.
• I have checked that no Personal Identifiable Data (PID) is logged as part of the changes.

[github-actions]

This branch is working on a ticket in the NHS England VED JIRA Project. Here's a handy link to the ticket:

VED-981

[dlzhry2nhs]

Is it worth putting the stream and publisher Lambda function behind a switch in terraform? We might want to have off by default in envs other than internal-qa, int, and prod, but allow a developer to switch on if working on a PR environment.

Otherwise could be a lot of noise for PDS with invalid testing patients from our pipeline runs?

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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