JCLOUDS-1223: Use larger block blobs for Azure

This raises the maximum multipart size from 195 GB to 4.77 TB.
Reference:

https://azure.microsoft.com/en-us/blog/general-availability-larger-block-blobs-in-azure-storage/

providers/azureblob/src/main/java/org/jclouds/azureblob/blobstore/AzureBlobStore.java

@@ -492,7 +492,7 @@ public class AzureBlobStore extends BaseBlobStore {
 
    @Override
    public long getMaximumMultipartPartSize() {
-      return 4 * 1024 * 1024;
+      return 100 * 1024 * 1024;
    }
 
    @Override