Added AwaitsFix
Aggregations parsing is too lenient.

Close #5827
include thread name when logging IndexWriter's infoStream messages
Provide meaningful error message if field has no fielddata type

closes #5930
[DOC] Fixed filtered_query typo
Fix computation of the missing ord (leftover of the ordinals change).
add thread name to logger message from IndexWriter's infoStream
Range/Term query/filter on dates fail to handle numbers properly
When providing a number (milliseconds since epoch, UTC), range and term query/filter don't handle it correctly and convert it to a string, that is then first tried to parse as a date
closes #5969
Added global ordinals based implementations for significant terms aggregator.

Closes #5970
[REST-SPEC] update to update test, to check for es-js error messages
disable using CBOR in randomized test infra
due to a bug in CBOR handling long values (test case to verify it is included), disalbe using CBOR in our tests till it gets fixed
Upgrade to Jackson 2.3.3
fixes the long value bug as well...
Fix setting of readerGen in BytesRefOrdValComparator on nested documents.

Sorting was broken on nested documents because the `missing(slot)` method
didn't correctly set the segment ordinal (readerGen), causing term ordinals to
be compared across segments.

Close #5986
Improve the way sub-aggregations are collected.

Sub-aggregations are currently collected directly, by just forwarding the
doc ID and bucket ordinal to them. This change adds the new BucketCollector
abstract class that Aggregator extends, so that we have more flexibility to
add implicit filters or buffering between an aggregator and its sub
aggregators.

Close #5975
ThreadPool.EstimatedTimeThread should be set on initialization

Some tests run before the thread is started and thus use 0 as a the current time, which later on leads to big time jumps and thus failures.
Ex. InternalEngineTests.testVersioningReplicaConflict2
Use collectExistingBucket in GlobalOrdinalsStringTermsAggregator.WithHash.

Relates to #5955.
Run tests through forbidden-apis.
Use collectExistingBucket in GlobalOrdinalsSignificantTermsAggregator.WithHash.

Relates to #5955.
Added `reverse_nested` aggregation.

The `reverse_nested` aggregation allows to aggregate on properties outside of the nested scope of a `nested` aggregation.

Closes #5507
Fixed license headers.