COMP: merge with develop and solve confict (python3)

CMake/CTestCustom.cmake.in

CMake/OTBModuleDoxygen.cmake

CMake/OTBModuleHeaderTest.cmake

CMakeLists.txt

Documentation/Cookbook/CMakeLists.txt

Documentation/Cookbook/rst/Installation_Linux.rst

Documentation/Cookbook/rst/Installation_Macos.rst

Documentation/Cookbook/rst/Installation_Windows.rst

Modules/Wrappers/SWIG/otb-module-init.cmake

Modules/Wrappers/SWIG/src/CMakeLists.txt

Modules/Wrappers/SWIG/src/python/CMakeLists.txt

Modules/Wrappers/SWIG/src/python3/CMakeLists.txt

Packaging/CMakeLists.txt

Packaging/CTestConfig.cmake

Packaging/Files/selftester.bat

Packaging/Files/selftester.sh

Packaging/Files/setup_python.sh

Packaging/Files/uninstall_otb.bat

Packaging/Files/uninstall_otb.sh

Packaging/check_cmake_variables.cmake