docs: include guidance to enable SPN-based auth

microsite/docs/ConnectingData/Azure.md

@@ -69,4 +69,6 @@ By default, the application authenticates with Azure using environment variables
 
 The authentication mode is set inside [packages/common/src/Config.ts](https://github.com/cloud-carbon-footprint/cloud-carbon-footprint/blob/trunk/packages/common/src/Config.ts), and you can see these options being used in [packages/azure/src/application/AzureCredentialsProvider.ts](https://github.com/cloud-carbon-footprint/cloud-carbon-footprint/blob/trunk/packages/azure/src/application/AzureCredentialsProvider.ts).
 
+To establish authentication with Azure using a Service Principal (SPN) and a certificate, the initial steps involve creating them in Azure as outlined in [this guide](https://learn.microsoft.com/en-us/cli/azure/azure-cli-sp-tutorial-1?tabs=bash). Additionally, ensure that the AZURE_AUTH_MODE is configured to "CERTIFICATE" and AZURE_CERTIFICATE_PATH is set to path of your certificate to enable SPN-based authentication.
+
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