Style helper enhancements

[gpeairs]

For methods not_solidmodel, only_solidmodel, not_simulated, only_simulated

• Export not_solidmodel, only_solidmodel from SchematicDrivenLayout
• Add in-place only_solidmodel!(::GeometryStructure) etc
• Helpers for applying styles to Paths: not_simulated(pa::Path) = not_simulated(simplify(pa)) etc, also for meshsized_entity
  • In-place versions will require a way to apply a GeometryEntityStyle via a Paths.Style (or some kind of styled structure wrapper but that seems unwise)