Support for JDK 14 record types

(note: created based on https://github.com/FasterXML/jackson-future-ideas/issues/46)

With JDK 14 Java will get Record type of classes. While it appears that they can already be used with right set of configuration options, it would probably make sense to add explicit support to maybe use different auto-detect defaults. Support should be done in a way that does not require JDK 14 dependency by jackson-databind (that is a leap too far even for 3.0 at least as of May 2020): either so that

1. If possible, detection simply uses existing JDK functionality (assuming enough features are translated into bytecode accessible using JDK 8 methods), OR
2. If support does require JDK 14 API, create another module (jackson-module-jdk14 or jackson-datatype-jdk14, depending).

Marking tentatively as 3.0, but may be moved to a 2.x version if and when someone actual works on this.

[cowtowncoder]

Released as part of Jackson 2.12.0.

[cowtowncoder]

And there! It is done – initial implementation at any rate.

If anyone wants to check it out that would be highly appreciated. The highest value contribution would probably be addition of tests in RecordTest under src/test-jdk14/java (same test class or new ones whatever) – I suspect that there may be edge cases wrt handling of annotations, mostly on deserialization side.