Add some Ion-to-Native and Native-to-Ion conversion utilities

[jobarr-amzn]

In another channel a user suggested adding additional conversion utilities, including the ability to convert an entire IonPyDict to a native dict type.

[rmarrowstone]

Conceptually, IonPy types were designed with the idea that they are the native python type and that the native python can substitute for them. This duck-typing, seems at face value, a "pythonic" way to model them.

Unfortunately, user's expectations for how they work are different than reality. That be something about how they were modeled, or potentially the imperfection of the implementation. I don't think it's the foundational premise (which seems sound to me), but I don't know.