Implement a cache feature for EnrichRecordsElasticsearch processor

[Mathieu Rossignol]

Suppose you receive multiple web events from same user and you use EnrichRecordsElasticsearch processor to enrich webevents (records) with additional user information from an ES index. You don't want to grab the same information again and again if the additional fields from the ES user index are not changing often. In that case, with a cache feature for the EnrichRecordsElasticsearch processor, you may improve a lot performances as you won't grab additional info from ES at each webevent.

[Mathieu Rossignol]

Done