Add Elasticsearch specific ResultsWriter to benchmarks.

[christophstrobl]

Elasticsearch offers a broad variant of data analytics and time series options. Enhance the raw json data generated by the JMH ResultFormatFactory to include the following information and split the benchmark result array into individual benchmark results to be pushed to Elasticsearch.

property	type	description
date	DateTime	Date and time the benchmark was run Required for time series analysis.
project_name	String	The project name under test eg. spring-data-mongodb
project_version	String	The project version under test eg. 2.1.0.RC1.
snapshot	boolean	Additional field for filtering out snapshot data quickly.
git_commit	String	The git commit sha
benchmark_group	String	The simple name of the actual Class file holding the benchmark.
benchmark_name	String	The benchmark method name.