Add support for uploading entire directories to Azure blob storage

[chester-leung]

Currently, MC² Client doesn't support uploading entire directories to Azure blob storage. We'd like to add support for this, as data encrypted in sql format is always outputted as a directory with a data sub-directory and a schema sub-directory.

To do this, we'll have to investigate how to upload/download directories to/from Azure blob storage using the Azure Python SDK, and modify the upload_data() and download_data() functions.