Wait for green after indexing doc, so that the mapping update is always after the index operation on replica has completed. (replica shard may needed to catch up)
fixed nested example response in docs

Closes #4935
Improve test stability
Added dedicated thread pool cat api, that can show all thread pool related statistic (size, rejected, queue etc.) for all thread pools (get, search, index etc.)
By default active, rejected and queue thread statistics are included for the index, bulk and search thread pool.
Other thread statistics of other thread pools can be included via the `h` query string parameter.

Closes #4907
Remove waiting for green in CopyToMapperIntegrationTests
Add throttling to snaphost and restore operations

Closes #4855