Use builder for prefetch CachingBlockManager

Some of the recent changes (HADOOP-18399, HADOOP-18291, HADOOP-18829 etc) have added more params for prefetch CachingBlockManager c'tor to process read/write block requests. They have added too many params and more are likely to be introduced later. We should use builder pattern to pass params.

This would also help consolidating required prefetch params into one single place within S3ACachingInputStream, from scattered locations.