Add support of exposing meta_server_grains for Azure VMs

[guvishal989]

What does this PR do?

Add support of exposing meta_server_grains for Azure VMs

Previous Behavior

setting metadata_server_grains: True in minion conf was not exposing cloud meta data grains in case of Azure VM

New Behavior

setting metadata_server_grains: True in minion conf will be exposing cloud meta data grains in case of Azure VM

[welcome]

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[guvishal989]

@garethgreenaway Please review.

[welcome]

Congratulations on your first PR being merged! 🎉