VanillaPlus Structures

### v20
- Improve handling of vanilla engrams for modded structures when using `RemapAdditionalStructureEngrams`. Fixes some missing engrams and inventory count issues.
  *An issue still remains with certain modded engrams missing on load. Pickup and re-place as temporary workaround. This is related to other mods mixed usage of modified default inventory and the additional structure engrams in mod data asset. Improved handling for this specific case will come soon.*
- Minor function library improvements:
  - `parseStructureClassNames` no longer attempts its own structure discovery. An array of available structures is required.