add TAG After backup azure VM

@liorkrispin interesting to learn about the use-case! Anyhow as far as I know this is not possible without adding it yourself via a script that communicates to the Azure API endpoint to place the tag.

While thinking about it myself I do see some use-cases here, especially in larger enterprise environments. Adding the tag allows others to retrieve the backup status of a VM (using API/SDK) without the need to open the Commvault portal or look into reports. I would definitely consider opening a CMR for it to be added for Azure, AWS and VMware.