[Identity] Support cross-tenant authentication

[jianghaolu]

Support the scenario described in https://docs.microsoft.com/bs-latn-ba/azure/azure-resource-manager/authenticate-multi-tenant.

To test it, the shared image gallery scenario takes advantage of this type of authentication header: https://docs.microsoft.com/en-us/azure/virtual-machines/linux/share-images-across-tenants

A previous issue which users were able to workaround: #3819. We need to provide a more elegant way.

[jianghaolu]

The customer that reported this is using the track 1 management SDKs so this might have to be done also in autorest-clientruntime-for-java.