* Re-create PR #4527 from @arcolife:
fixes #4526 - add nested support to fieldname autocomplete; Also:
    - update _mapping to first use given time range
      for deducting index mapping, then fallback to
      today's date based index name

* (elasticsearch): refactor getFields() method.

* (elasticsearch): add tests for getFields() method.

* (elasticsearch): fixed _get() method (tests was broken after @arcolife commit).

ref #5981

ref #5981

tech(lib upgrade): fixed issue with angular 1.5.8, so can revert revert of upgrade, that is we are no on latest angularjs, #6022

Instead of allowing users to access the
entire cluster, apply some sane restrictions.

Change-Id: Ib2e93722bf2e39d700d4afa713ff49ec556f2fdf