enhance authentication to azure (drop azure-ruby-sdk)

[tbugfinder]

Describe the Enhancement:

I'd like to use rather temporary credentials while using "az login".
This setup does not depend on environment variables like AZURE_TENANT_ID (...).
Also it's time to drop the deprected azure-ruby-sdk as it is no longer maintained.
https://github.com/inspec/train/blob/main/train.gemspec#L36-L40
https://github.com/Azure/azure-sdk-for-ruby#important-announcement

https://github.com/inspec/train/blob/main/lib/train/transports/azure.rb#L15-L19

Describe the Need:

Updated authentication methods should be used instead of environment variables only.

Current Alternative

Just noticed that I have to look into ENV["AZURE_CRED_FILE"].

Can We Help You Implement This?:

I cannot implement this enhancement request.