* Add parent-join module
This change adds a new module named `parent-join`.
The goal of this module is to provide a replacement for the `_parent` field but as a first step this change only moves the `has_child`, `has_parent` queries and the `children` aggregation to this module.
These queries and aggregations are no longer in core but they are deployed by default as a module.
Relates #20257
This commit adds support for histogram and date_histogram agg compound order by refactoring and reusing terms agg order code. The major change is that the Terms.Order and Histogram.Order classes have been replaced/refactored into a new class BucketOrder. This is a breaking change for the Java Transport API. For backward compatibility with previous ES versions the (date)histogram compound order will use the first order. Also the _term and _time aggregation order keys have been deprecated; replaced by _key.
Relates to #20003: now that all these aggregations use the same order code, it should be easier to move validation to parse time (as a follow up PR).
Relates to #14771: histogram and date_histogram aggregation order will now be validated at reduce time.
Closes#23613: if a single BucketOrder that is not a tie-breaker is added with the Java Transport API, it will be converted into a CompoundOrder with a tie-breaker.
* QueryBuilders.queryString is now QueryBuilders.queryStringQuery
* DateHistogram.Interval is now DateHistogramInterval
* Refactoring of buckets in aggs
* FilterBuilders has been replaced by QueryBuilders
Closes#9976.
The Histogram and Range APIs for the aggregations changed so that there was a common interface between he types of Range/Histogram. This PR reflects that change in the Java API docs
Contributes to #9976
Combalgorythm
Jim Ferenczi
qwerty4030
David Pilato
Adrien Grand
Colin Goodheart-Smithe
Colin Goodheart-Smithe