Elasticsearch integration 

Changes include
 - KeyValue Store interface, rtgov-common
 - ElasticsearchKeyValueStore impl in rtgov-elasticsearch
   - Configurable with index, type and ES host list 
 - ElasticSearchProcessor in ep-elasticsearch 
 - Additional  quickstart which demonstrates ES functionality. 
    - Stores activityunits, responsetime and situation models
    - demonstrates ES preconfiguration using rtgov-mapping.json file($indexname-mapping.json)
    - deployed with sla quickstart and generate events using ActvitiyClient