RTGOV-415 : Elasticsearch activityStore

- Includes, 
   - Elasticsearch Actvitystore  test requires a running ES server (setups and tears down of rtgovtest index)
   - Mapping initialization checks for child documents belonging to parent document
   - Elasticsearch activitystore is not integrated with RTGov(as replacement for jpaactivitystore). Currently only testcase. 
   - ES activities stored under the following index by EPN
      - rtgov/activity => Parent 
      - rtgov/activitytype  => Child (child documents initialized depending on definitions in -mapping.json file)
  
todo
   - Remove Activity and situation EPN
   - Replace with ES activitystore  and ES situation store