Provide Java client for fetching Yarn specific entities from TimelineReader

While reviewing YARN-8303, we felt that it is necessary to provide TimelineReaderClient which wraps all the REST calls in it so that user can just provide application or container ids along with filters.Currently fetching entities from TimelineReader is only via REST call or somebody need to write java client get entities.

It is good to provide TimelineReaderClient which fetch entities from TimelineReaderServer. This will be more useful.