cmake _vtk_third_party_external_PACKAGE examples

Kitware/VTK CMake/vtkModule.cmake :6033 

find_package("${_vtk_third_party_external_PACKAGE}"
      ${_vtk_third_party_external_VERSION}
      ${_vtk_third_party_external_config}
      COMPONENTS          ${_vtk_third_party_external_COMPONENTS}
      OPTIONAL_COMPONENTS ${_vtk_third_party_external_OPTIONAL_COMPONENTS})