Investigate adding constrained type transformations

[PathogenDavid]

Occasionally it only makes sense for a particular type reference to be a TranslatedTypeReference. However, in order to properly work with type transformations you have to support the extremely general TypeReference. We should either explicitly support constrained type transformations or investigate the ramifications of silently(?) dropping type transformations that violate a transformation constraint.

Semi-realted: https://github.com/InfectedLibraries/Biohazrd/issues/151 since metadata frequently describes relationships rather than type references.