[scan1] decisive simplification of scan resolution evaluation ()

Param/Distrib/RangedDistributions.cpp

Param/Distrib/RangedDistributions.h

Sim/Export/SimulationToPython.cpp

Sim/Scan/AlphaScan.cpp

Sim/Scan/AlphaScan.h

Sim/Scan/ISpecularScan.cpp

Sim/Scan/ISpecularScan.h

Sim/Scan/QzScan.cpp

Sim/Scan/QzScan.h

Sim/Scan/ScanResolution.cpp

Sim/Scan/ScanResolution.h

Tests/Unit/Param/RangedDistributionTest.cpp

Tests/Unit/Sim/ScanResolutionTest.cpp

auto/Wrap/libBornAgainSim.py

auto/Wrap/libBornAgainSim_wrap.cpp