DRILL-6953: Merge row set-based JSON reader
* Snapshot: reworked JSON field parser creation
* Updated JSON loader
* Redo value listener with tokens
* Extended long type works
* More simple extended types
* Added $date
* Binary type
* All extended type except arrays
* Extended arrays partly working
* More arrays work
* Refactor element parser interfaces
* Rename RowSetTests --> RowSetTest
* More factory cleanup
* Revised unknown field creation
* In middle of factory/parser restructuring
* Scalars, object, some variants work again
* JSON loader tests pass
* File cleanup
* Old extended types test passes
* Renamed JSON packages
* Tested extended provided types
