Azure Blob Storage storage implementation

## Description
We are looking to use Blue Brain Nexus in the Microsoft Azure cloud. One thing which is relevant for us is to use an object store for file storage which is covered in Nexus only via the `S3Storage` implementation. For Azure-based deployments, it's ideal to use [Azure Blob Storage](https://azure.microsoft.com/en-us/products/storage/blobs) which is S3's counterpart. Interacting with ABS is already implemented via a [client library](https://mvnrepository.com/artifact/com.azure/azure-storage-blob#:~:text=,48%E2%80%A0149%20artifacts%E3%80%91), so in theory it's only necessary to wrap them in Nexus abstractions.

I wanted to get a feel of whether the storage classes in Nexus are curated in a way that would prevent contribution adding support for other providers. Also, I'm curious of the approximate effort necessary to implement this feature, as this is something that our team could potentially take on.

For now we are weighing our options. An easy/hacky alternative for us is to simply not push files directly through Nexus and only create the appropriate resources to represent the file as some ABS entity.

Start by reviewing the existing S3Storage implementation and the Azure Storage Blob client library linked in the issue. Determine how Azure Blob Storage could be wrapped in Nexus abstractions; done would mean a defined implementation approach, though the issue does not name files, tests, or acceptance criteria.

Written by the indexing model from the issue text.