General availability: Enable hierarchical namespace for existing Azure Storage accounts

The ability to enable the Azure Data Lake Storage [hierarchical namespace](https://docs.microsoft.com/azure/storage/blobs/data-lake-storage-namespace) for existing accounts is now generally available. The hierarchical namespace optimises Azure Storage accounts for use in big data analytics scenarios while not forcing the creation of a separate silo of data. The ability to enable the hierarchical namespace for accounts containing existing data allows those customers that are already benefiting from the cost and performance benefits of Azure Storage to gain even more benefit. Existing data may be consumed in a more performant way as a genuine file system by big data analytics frameworks, such as Spark, Hive, Presto, Synapse SQL Serverless and others. Additionally, features such as [POSIX-compliant Access Control Lists](https://docs.microsoft.com/azure/storage/blobs/data-lake-storage-access-control) allow permissions to be assigned at the individual directory or file level and have those permissions propagate throughout the directory structure. To learn how to upgrade your Azure Storage account to enable the hierarchical namespace as well as guidance for how to plan for this, please read our documentation [concept article](https://docs.microsoft.com/azure/storage/blobs/upgrade-to-data-lake-storage-gen2) and [how-to guide](https://docs.microsoft.com/azure/storage/blobs/upgrade-to-data-lake-storage-gen2-how-to). * Azure Data Lake Storage * Features * Services