Add Azure Blob Storage configuration
Unlike AWS and Google, Azure needs to use an Azure client inside Workhorse to support direct uploads. Using standard HTTP transfers with pre-signed URLs with the Azure Put Blob API (https://docs.microsoft.com/en-us/rest/api/storageservices/put-blob) doesn't work because Azure doesn't support chunked transfer encoding. However, Azure does support uploading files in segments via the Put Block and Put Block List API (https://docs.microsoft.com/en-us/rest/api/storageservices/put-block), but this requires an Azure client.
To support this, this commit extracts the Azure Fog credentials from the Rails connection information and adds them to the Workhorse configuration.
This changes requires two merge requests to work:
Part of gitlab#25877 (closed)
Edited by Stan Hu