Add static accessor/mutator conveniences

[feltech]

What

Generate static conveniences for trait accessors/mutators, such that the (C++) refcount of the TraitsData is not modified.

Why

C++ purists will balk at wrapping a TraitsData in a short-lived trait view to operate on it, likely necessitating a shared_ptr copy and refcount bump. This is a potentially measurable performance hit in large-volume operations.

E.g. we can add static variants such as getLocationFrom(const TraitsData&), and similarly setLocationTo.