replace IFormFactor by IBornFF where possible

GUI/Model/Sample/FormFactorItems.cpp

GUI/Model/Sample/FormFactorItems.h

Sample/ComponentBuilder/FormFactorComponents.h

Sample/Particle/Particle.cpp

Sample/Particle/Particle.h

Sample/StandardSamples/LayersWithAbsorptionBuilder.cpp

Sample/StandardSamples/LayersWithAbsorptionBuilder.h

Sample/StandardSamples/ParticleInVacuumBuilder.cpp

Sample/StandardSamples/ParticleInVacuumBuilder.h

Tests/Functional/Std/StandardTests.h

auto/Wrap/doxygenSample.i

auto/Wrap/libBornAgainSample.py

auto/Wrap/libBornAgainSample_wrap.cpp