Investigate if Jackson 2.15 provided "fast floating-point" improves BigDecimal reads, enable

[tatu-at-datastax]

(similar to #652 but for reading)

As per: https://medium.com/@cowtowncoder/jackson-2-15-yet-faster-floating-point-reads-fd6d5a0b769a Jackson 2.15 and later have opt-in "fast FP reads" feature, which has measurable performance benefit for reading float/double (and wrapper) values. If it also helps with BigDecimal (to be investigated), we should enable this given that the incoming JSON document often has huge vectors (read: tons of FP values) to decode.

Existing test(s) in: https://github.com/FasterXML/jackson-benchmarks should be possible to modify to test out low-level performance difference, if any; and if proven to help with BigDecimal should enable setting.

[tatu-at-datastax]

As per https://medium.com/@cowtowncoder/jackson-2-16-faster-bigdecimal-reads-b65eb127b899 there is measurable improvement in performance, but I am still hoping to test a more "FP-heavy" case to quantify benefit for Vector use case.

For somewhat lighter case discussed in above blog post, performance improvement for JSON doc with big Object with keys, short FP numbers, was +10%. Still worth it so will proceed one way another soon.