ENH: Changing static class for dedicated namespace, as suggested on otb-developers

...s/Adapters/GdalAdapters/include/otbOGRDataSourceWrapper.h

...Adapters/GdalAdapters/include/otbOGRDataSourceWrapper.txx

Modules/Adapters/GdalAdapters/include/otbOGRLayerWrapper.h

Modules/Adapters/GdalAdapters/include/otbOGRVersionProxy.h

...les/Adapters/GdalAdapters/src/otbOGRDataSourceWrapper.cxx

Modules/Adapters/GdalAdapters/src/otbOGRLayerWrapper.cxx

Modules/Adapters/GdalAdapters/src/otbOGRVersionProxy1x.cxx

Modules/Adapters/GdalAdapters/src/otbOGRVersionProxy2x.cxx

Modules/IO/IOGDAL/include/otbOGRIOHelper.h

Modules/IO/IOGDAL/include/otbOGRVectorDataIO.h

Modules/IO/IOGDAL/src/otbOGRIOHelper.cxx

Modules/IO/IOGDAL/src/otbOGRVectorDataIO.cxx

Modules/IO/TestKernel/src/otbTestHelper.cxx