Add REST endpoint under /ws/v1/samza at tracking url

[llamahunter]

The Samza AM REST endpoint is currently not available from the RM REST api. This may be a bug with the RM, but note that:

a) this is not the way the MapReduce AM exposes it's REST endpoint
b) the Samza REST endpoint is currently unversioned (also unlike the RM and MapReduce REST endpoints)
c) the Samza REST endpoint is not using the RM proxy mechanism for security.

[llamahunter]

See also https://issues.apache.org/jira/browse/YARN-4191

[heipacker]

Recently we want to develop a demand, is that I want to get to the node log address, so we need to get to this RPC port, but at this stage we can not get the port, and now we can only through the HTML file, can we expose this RPC port by HTTP server webapp?

[heipacker]

if we use the hadoop admin page, when we search the log, we need too many operations. so we make this demand.