Jackson ObjectMapper factory

This module provides default setup of Jackson ObjectMapper for handling JSON across multiple Lambdas in the same way. It comes with Java Time API (JDK8) module loaded. It’s also configure to ignore unknown properties during deserialization for better flexibility (so that one can use partial models and also be future-compatible as much as possible). Dates are configured to be serialized as timestamps (doesn’t mean Unix timestamps - just a string representation, instead of atomic properties).