struct NaturalToHLCPPTraits

Helper trait to describe how a type in the natural bindings can be converted to a type in the

HLCPP bindings. Every specialization of this trait should have a `using HLCPPType` type alias to

indicate the type in the HLCPP bindings and a `static HLCPPType Convert(Natural

&

&

)` method to do

the conversion.