DiskDirectoryBlobStorage saves Metadata Attribute files unencrypted if encryption is set in the pipeline

[dammitjanet]

I assume this will be the same for ZipFileBlobStorage and will need a change to include it since it targets the Blob objects and not the content streams.

SinkedBlobStorage which is used when sinks are in use, needs to implement a new interface to cater for the retrieval of Blob objects when the sink is transformed as follows:

Task<IReadOnlyCollection<Blob>> GetBlobsAsync(IEnumerable<string> fullPaths, CancellationToken cancellationToken = default)
Task<IReadOnlyCollection<Blob>> ListAsync(ListOptions options = null, CancellationToken cancellationToken = default)
Task SetBlobsAsync(IEnumerable<Blob> blobs, CancellationToken cancellationToken = default)

[robinrodricks]

Please file a PR for this if you have time. Thanks!