Add CODEOWNERS & Fix Sentinel Simplified Pricing

[jtracey93]

Overview/Summary

Add CODEOWNERS & Fix Sentinel Simplified Pricing

This PR fixes/adds/changes/removes

1. Add CODEOWNERS for accelerator/** flexibility in PR approvals
2. Add capability to handle new Sentinel simplified pricing model released in July 2023, as explained here: https://learn.microsoft.com/azure/sentinel/enroll-simplified-pricing-tier?tabs=microsoft-sentinel#change-pricing-tier-to-simplified
3. Fixes [Sentinel] - Error occurs when deploying Sentinel in a new Azure tenant  #581

Breaking Changes

1. Technically not a "true" breaking change - but these changes by default will set/convert the pricing tier on sentinel to the new simplified pricing tier (https://learn.microsoft.com/azure/sentinel/enroll-simplified-pricing-tier?tabs=microsoft-sentinel#change-pricing-tier-to-simplified) for existing deployments of the solution.
   • You can stop this by setting the Boolean parameter for parUseSentinelClassicPricingTiers for the logging.bicep module to true

Testing Evidence

With params set to:

• parUseSentinelClassicPricingTiers = true

With params set to:

• parUseSentinelClassicPricingTiers = false (default for module)

Note: No removal of sku property

As part of this Pull Request I have

• Read the Contribution Guide and ensured this PR is compliant with the guide
• Ensured the resource API versions in .bicep file/s I am adding/editing are using the latest API version possible
• Checked for duplicate Pull Requests
• Associated it with relevant GitHub Issues
• (ALZ Bicep Core Team Only) Associated it with relevant ADO Items
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated one or more of the following tests (if required)
  • Unit
  • Linting
  • E2E (End-To-End)
  • ValidateAzCloud (Base validation in Azure Cloud)
  • ValidateMcCloud (Base validation in Azure China Cloud)
• Updated relevant and associated documentation (e.g. Contribution Guide, Module READMEs, Wiki Docs etc.)
• If relevant, created or updated Code Tours here

[jtracey93]

/azp run validateazcloud

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[oZakari]

Looks good