Add IO adapter/datatype module for FasterXML Jackson

[sciwhiz12]

We currently provide IO adapters for google/gson and square/moshi, two popular JSON libraries for the JVM.

For more options for consumers, we should also look into providing an IO adapter for FasterXML/jackson. Specifically, we would provide a "datatype module" -- a Module which can be registered to ObjectMapper.registerModule -- so Jackson's databind package can read and write our objects.

They'll be hooked up into the standard battery of IO tests we have already, to ensure there are no regressions or mismatched behaviors.