Aggregation Support for Range Fields

[nknize]

The original Range Field PR (#21002) included a CustomRangeDocValuesField for enabling doc values on Lucene Range Field types. One reason it was removed is because Aggregations have no way of leveraging range fields; so I am opening this issue to solicit ideas on adding range field support to aggregations. For relevant bucket aggregations (e.g., histogram, range, date_histogram, date_range, ip_range) it seems the simple way is to count the document if the indexed range INTERSECTS with the bucket range? There are also a lot of interesting things (e.g., distribution stats) we could do for supporting range fields in existing metric aggregations (stats, extended_stats, etc). I don't want to overthink this but it seems like there are several different directions we could go here; and we had some questions around this topic at elasticon AMA, so I'd like to start gathering some thoughts.

[jpountz]

Relates to #23182.

[nknize]

Oh hay!! I might have seen that one if I didn't have 265K unread emails! Thanks @jpountz! Closing this issue as a duplicate.