[Chore] Export basic types appear in arguments and return types

[ciscorn]

(Thank you for creating a great library!)

What technical task needs doing?

When integrating Terra Draw, I'm having difficulty annotating my code with Terra Draw's types because they are not exported.

Exporting basic types that appear in the public interfaces should improve usability and integration.

[neodescis]

I've run into this as well, specifically with types for on/off callbacks, FeatureId, NumericStyling and HexColorStyling, but I'm sure there are others.