Also changed the stash logger to not log all stashed values under debug (it does trace now) but do dump the stash content upon failure (under info as a XContent)
Extends ShardStats with commit specific information. We currently expose commit id, generation and the user data map.
The information is also retrievable via the Rest API by using `GET _stats?level=shards`
Closes#10687
Bugs:
* "groups" and "types" were being ignored
* "completion_fields" as wildcards were not being resolved to fieldnames
Enhancements:
* Made "groups" and "types" support wildcards
* Added missing tests
Closes#6390
Boaz Leskes
Zachary Tong
Clinton Gormley