Provide Managed identity support for authentication

[abharku]

Our organisation has adopted complete key less authentication and only use managed identities for any auth in Azure.

Detailed Description

Managed identity in Azure provides a way to authenticate with Azure using AD and it gives us a way to not having service principals or keys which can create vulnerability at times. With MI support we can run inspec in computes in Azure and use identity of VM or aci to run inspec profile.

Context

I am unable to implement inspec is my current organisation as service principals are negated through policies.

Possible Implementation

There is a ruby module already but this is just a suggestion https://github.com/Azure-Samples/resources-ruby-manage-resources-with-msi