REFAC: remove ParameterType_Empty

Documentation/Cookbook/Scripts/otbGenerateWrappersRstDoc.py

Documentation/Cookbook/rst/recipes/python.rst

Examples/Application/ApplicationExample.cxx

...ations/AppClassification/include/otbTrainDecisionTree.hxx

...AppClassification/include/otbTrainGradientBoostedTree.hxx

...tions/AppClassification/include/otbTrainRandomForests.hxx

Modules/Applications/AppSegmentation/app/otbSegmentation.cxx

Modules/Applications/AppTest/app/otbTestApplication.cxx

...rappers/ApplicationEngine/include/otbWrapperApplication.h

...ppers/ApplicationEngine/include/otbWrapperBoolParameter.h

...pers/ApplicationEngine/include/otbWrapperEmptyParameter.h

Modules/Wrappers/ApplicationEngine/include/otbWrapperTypes.h

.../Wrappers/ApplicationEngine/src/otbWrapperApplication.cxx

...licationEngine/src/otbWrapperInputProcessXMLParameter.cxx

...icationEngine/src/otbWrapperOutputProcessXMLParameter.cxx

...appers/ApplicationEngine/src/otbWrapperParameterGroup.cxx

...rappers/CommandLine/src/otbWrapperCommandLineLauncher.cxx

Modules/Wrappers/QGIS/src/otbQgisDescriptor.cxx

...ppers/QtWidget/include/otbWrapperQtWidgetEmptyParameter.h

Modules/Wrappers/QtWidget/src/CMakeLists.txt