It should not return next_page_after_value when it reaches end of data

Fixed issue with too early break in nested_object_keys loop: the loop now runs to the end but only stores the longest found nested key.

Created a new hook for scrolling through the list of query results using ES search_after, fixed an API issue where the wrong 'next_page_after_value' was reported.

Slider min/max values are now updated by using aggregation that is independent of the query. Fixed API problems with automatic casting of range values into integers.