JCLOUDS-671: Modify AzureBlobUploadStrategy to use Iterable payload

Payload slicer has a method that returns an iterable of payloads that works on non-repeatable
InputStreams that was introduced to fix multi-part uploads in swift (JCLOUDS-356). This commit
applies the same method to fix multi-part uploads for azure blob store.

https://issues.apache.org/jira/browse/JCLOUDS-671