Support for Azure Environments (Sovereign Clouds, like Azure Government)

Right now, the ng-deploy-azure system doesn't support specifying alternative Azure Environments (such as sovereign clouds, like AzureUSGovernment or AzureGermanCloud)

Please add configuration in azure.json to support specifying other clouds. This also implies that authentication can be done against other clouds, and the Azure Storage URL suffixes can be modified to support other clouds.