Migrate overlays from FunctionApp to LinuxFunctionApp

[danielrbradley]

When using one of the overlays to add an inline callback function, internally it's using the FunctionApp and appservice.Plan which are now deprecated:

// Create an Azure Function to subscribe to the output and print all outputs of the job
outputHub.onEvent("analytics-output", {
    callback: async (context, event) => {
        console.log(JSON.stringify(event));
    },
});

warning: urn:pulumi:dev::azure-ts-stream-analytics::azure:eventhub/eventHub:EventHub$azure:eventhub:EventHubSubscription$azure:appservice/functionApp:FunctionApp::analytics-output verification warning: The `azurerm_function_app` resource has been superseded by the `azurerm_linux_function_app` and `azurerm_windows_function_app` resources. Whilst this resource will continue to be available in the 2.x and 3.x releases it is feature-frozen for compatibility purposes, will no longer receive any updates and will be removed in a future major release of the Azure Provider.

We need to migrate these to use the LinuxFunctionApp and appservice.ServicePlan instead.

Ideally this should migrate without re-creation.