[YARN-3368] REST API related changes for new Web UI

Following things need to be added for AM related web pages.

1. Support task state query param in REST URL for fetching tasks.
2. Support task attempt state query param in REST URL for fetching task attempts.
3. A new REST endpoint to fetch counters for each task belonging to a job. Also have a query param for counter name.
i.e. something like :
/jobs/{jobid}/taskCounters
4. A REST endpoint in NM for fetching all log files associated with a container. Useful if logs served by NM.