[Hubs] Switch to a deployment stack

[flanakin]

⚠️ Problem

Resources are being left behind as we move from one version to the next when using Azure deployment templates.

🛠️ Solution

Switch to deployment stacks, which can clean up removed resources.

ℹ️ Additional context

See https://learn.microsoft.com/azure/azure-resource-manager/bicep/deployment-stacks?tabs=azure-powershell

🙋‍♀️ Ask for the community

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[flanakin]

Deployment stacks require a JSON template, so here's how I tested this...

1. cd src/scripts
2. ./Build-Toolkit finops-hub
3. cd ../../release/finops-hub
4. bicep build main.bicep
5. mv main.bicep ../../src/templates/finops-hub/test

6. In VS Code, edit the finops-hub/test/main.bicep file to be:

   targetScope = 'resourceGroup'
   
   param uniqueName string = 'ftk-hub-localtest1'
   param location string = 'westus2'
   
   resource stack 'Microsoft.Resources/deploymentStacks@2022-08-01-preview' = {
    name: 'stack-test'
    properties: {
      deploymentScope: resourceGroup().id
      description: 'FinOps hub'
      template: loadJsonContent('./main.json')
      parameters: {
        hubName: uniqueName
        location: location
      }
      actionOnUnmanage: {
        resources: 'delete'
      }
      denySettings: {
        mode: 'denyWriteAndDelete'
      }
    }
   }
   
   output hubName string = stack.id

7. cd ../../src/scripts
8. ./Deploy-Toolkit finops-hub -Test

Deployment is spinning forever, but if you look at the operation details in the deployment, you can see this error: Resource Provider has encountered an internal server error. Diagnostic information: timestamp '2023-10-05 09:16:09Z', request ID '5646a3c6-a259-43f0-8932-e4caf9b465e1', request correlation ID '02ef0d4d-6b56-4721-b9fc-3fe8c8465719'.

We'll need to try again in a future release. Seems it's not ready yet.