Feature Request: Azure Metadata Tags

[corey-hammerton]

What

• Provide a way to get Azure Virtual Machine Instance Tags, similar to gcp.Meta
• See https://learn.microsoft.com/en-us/azure/virtual-machines/instance-metadata-service?tabs=linux#sample-3-get-vm-tags

Why

• Improve support for a major Cloud Provider: Azure

Our Use Case

We use gcp.Meta on our Google Cloud infrastructure to help render configuration files on our Virtual Machines. We are building infrastructure in Azure and will require similar functionality

[hairyhenderson]

This almost happened in #1713 but I think it'd actually be better to access both GCP and Azure metadata as a filesystem - see hairyhenderson/go-fsimpl#322 as well.