Remove unused method SmrPlanetStructureType::getTypes
Remove unused method SmrPlanetStructureType::getTypes

Typically we only need to know what structure types a specific planet
type can build, not what structure types _any_ planet type can have.

hemberger/smr,hemberger/smr,hemberger/smr,smrealms/smr,hemberger/smr,smrealms/smr,smrealms/smr