Implement range aggregate types on ES-enabled content views

See NXS-2196: when simple aggregate types are dealt with, adapt to more complex aggregate types:

• range
  • ranges: MANDATORY list of:
    • String key: MANDATORY
    • String label: if null use key, do not handle translations for now
    • Double from: if null -infinity
    • Double to: if null infinity

• date_range
  • String format (joda date format http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-aggregations-bucket-daterange-aggregation.html
  • ranges: MANDATORY list of:
    • String key: MANDATORY
    • String label: if null use key, do not handle translations for now
    • String fromDate: if null -infinity, can be "now - 3w", date with format submitted
    • Double toDate: if null infinity,