Review legacy code and remove all that has been agreed safe to remove

[adecler]

Description:

There's quite a few old classes that feel like they should be removed (e.g. EnvironmentalProductDeclarationField, ProjectLifeCycleAssessment, LifeCycleAssessmentScope, GravityStructuralMaterial,...). Check with @michaelhoehn and @enarhi that they are safe to delete.