Allow use of `JsonNode` field for `@JsonAnySetter`

[sixcorners]

Is your feature request related to a problem? Please describe.
When working with unmapped nodes I want to work with JsonNode instead of Map.

Describe the solution you'd like
I want JsonAnySetter to support a field of the type JsonNode or maybe ObjectNode.

Usage example
class Test {
@JsonAnySetter
JsonNode extraData;
}
mapper.readValue("{"test": 3}", Test.class).extraData.path("test").intValue() == 3

Additional context
I'm a big fan of JsonNode.

[cowtowncoder]

Will be in 2.14.0.