Add FindTTB.cmake from VTK to CMake distribution
Kitware maintains the Find module as part of VTK source tree https://github.com/Kitware/VTK/blob/master/CMake/FindTBB.cmake
It is a well implemented module with consideration of detailed aspects of the configuration (e.g. build types, targets, etc.) and it does the job very well.
Although I am aware of CMake against Find-modules policy, I think this case is quite special as the module is maintained by Kitware, maintainer of CMake itself. It seems like it is just a matter of moving the FindTBB.cmake
file.