Add Azure Blob Storage support

This uses our custom Azure gem
(https://gitlab.com/gitlab-org/gitlab-fog-azure-rm) to integrate direct
upload access with GitLab.

Because the Azure Put Blob API does not work with chunked encoding,
uploads cannot be streamed directly via a pre-signed URL without saving
to disk first. To make this work without that, we need to add an Azure
client directly in Workhorse that uses the Put Block and Put Block List
API.

The Workhorse client is implemented in
https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/555. We
use the Go Cloud Development Kit to generate a URL
(e.g. `azblob://container`) that can be extended for other object
storage providers.

Part of https://gitlab.com/gitlab-org/gitlab/-/issues/25877