eli-285 and eli-349 adding cloudwatch alarms

[eddalmond1]

eli-285 and eli-349 adding cloudwatch alarms for a) security and b) ps - API Gateway and Lambda execution

Description

Adding alarms and an associated SNS topic for alarms to be pushed to. The eventual aim is to then use EventBridge to push the records to Splunk via the HEC Http Endpoint.

Context

Aim is to surface alerts related to live service to ITOC. Rather than push all logs, we can take a data minimisation approach and only push information which is actionable by ITOC.

Type of changes

• Refactoring (non-breaking change)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would change existing functionality)
• Bug fix (non-breaking change which fixes an issue)

Checklist

• I am familiar with the contributing guidelines
• I have followed the code style of the project
• I have added tests to cover my changes
• I have updated the documentation accordingly
• This PR is a result of pair or mob programming

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Sensitive Information Declaration

To ensure the utmost confidentiality and protect your and others privacy, we kindly ask you to NOT including PII (Personal Identifiable Information) / PID (Personal Identifiable Data) or any other sensitive data in this PR (Pull Request) and the codebase changes. We will remove any PR that do contain any sensitive information. We really appreciate your cooperation in this matter.

• I confirm that neither PII/PID nor sensitive data are included in this PR and the codebase changes.