JSON_VALUE/QUERY functions incorrectly map floating numbers

SELECT JSON_VALUE('{"bigNumber":123456789.987654321}', '$.bigNumber')

produces

"1.2345678998765433E8"

which can not be mapped back. It gets rounded.

The reason is we use double for floats in SqlJsonUtils. We should rather configure jackson to use BigDecimals. In order to do that we need to properly shade jayway though.

I suggest we:

1. Add com.jayway.jsonpath:son-path to flink-shaded
2. We use the shaded library and pass a configured mapper which maps floats to BigDecimal