Create new exception type `JsonNodeException` for use by `JsonNode`-related problems

[cowtowncoder]

With Jackson 3.0 we finally have JacksonException that is unchecked, and many methods in JsonNode (and subtypes) can start throwing JacksonException instead of various JDK exception types.
But we do not yet have a new type to use: let's add one.

Name could be JsonNodeException; I can start with that but we can also consider better names if anyone can suggest one. :)

[cowtowncoder]

Was added with an earlier commit, marking closed.