Stats and info changesedit

Removal of throttle_time in the store statsedit

Given that store throttling has been removed, the store stats do not report throttle_time anymore.

FS stats no longer reports if the disk spinsedit

Elasticsearch has defaulted to assuming that it is running on SSDs since the 2.x series of Elasticsearch. As such, Elasticsearch no longer needs to collect information from the operating system as to whether or not the underlying disks of each data path spin or not. While this functionality was no longer needed starting in the 2.x series of Elasticsearch, it was maintained in the filesystem section of the nodes stats APIs. This information has now been removed.