The benchmarks showed a sharp decrease in aggregation performance for
the UTC case.
This commit uses the same calculation as joda time, which requires no
conversion into any java time object, also, the check for an fixedoffset
has been put into the ctor to reduce the need for runtime calculations.
The same goes for the amount of the used unit in milliseconds.
Closes#37826
* Clean up s/ElasticSearch/Elasticsearch on docs/*
* Clean up s/ElasticSearch/Elasticsearch on src/* bin/* & pom.xml
* Clean up s/ElasticSearch/Elasticsearch on NOTICE.txt and README.textile
Closes#4634