Add tests for Gordon surface generation

[joergbrech]

We should consider testing tigl with Gordon surfaces activated for CPACS geometries. This concerns all geometries that can be created from a curve network, that is from section definitions and guide curves. Currently, this concerns fuselages, wings, engine nacelles and ducts.

One option would be to add a compile time switch to TIGL, which will activate the Gordon surface algorithm for all CPACS geometries and add a unit test to CI for at least one configuration with this switch enabled. This test can be removed once we fully migrate to the Gordon surface algorithm for our geometries in a future release.