extract blob upload resume into its own method
extract blob upload resume into its own method

I've found this logic being in a single method to be quite hard to get.
I believe extracting it makes it easier to read, as we can then more
easily see what the main method does and possibly ignore the intricacies
of `ResumeBlobUpload`.

Signed-off-by: Damien Mathieu <52b2ba1cdf714d3bf73611b264955688cc783e86@salesforce.com>

sadlil/distribution,docker/distribution,thaJeztah/distribution,sergeyfd/distribution,thaJeztah/distribution,docker/distribution,sergeyfd/distribution,sadlil/distribution