feat: dtoss 6235 create terraform module for azure event grid

[mrlockstar]

Description

Given* that I have access to the necessary Terraform and Azure resources,
When I create the Terraform module for Azure Event Grid,
Then the module should configure the Event Grid to be compliant with UK OFFICIAL standards,
And the module should ensure compliance with UK NHS policies,
And the module should adhere to the Azure Security Benchmark policies,
Or provide documentation for any deviations or exceptions.
Given that the module is deployed,
When the Azure Event Grid is provisioned,
Then it should pass all relevant compliance checks for UK OFFICIAL, UK NHS, and Azure Security Benchmark policies.
Given that there are updates to the policies,
When the module is reviewed,
Then it should be updated to maintain compliance with the latest UK OFFICIAL, UK NHS, and Azure Security Benchmark policies.

https://dev.azure.com/nhse-dtos/dtos-service-insights/_build/results?buildId=11419&view=results

Context

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.

[MacMur85]

Approved