Consider adding support for Builder-style construction (via annotation-support)

One popular way of creating value type instances is that of using Builder-style construction; especially with frameworks such as Lombok and Immutables. It would be great if jackson-jr supported this too.

One practical thing that is unfortunate is that we cannot really use standard Jackson annotations (`@JsonPOJOBuilder`) since that is not part of `jackson-annotations` (but `jackson-databind`).
So it would probably be necessary to add one or more annotations under `jr-annotation-support`.