Import cmake Modules/FindCUDA.cmake

Import cmake Modules/FindCUDA.cmake

CUDA 9.0 issues large numbers of -Wundef warnings from its internal
headers. FindCUDA.cmake should be including such headers as "system"
headers, so to prepare for a patch where it is modified to do that,
this commit imports that file from v3.4.3 of the CMake repository,
because that is a choice likely to work with all future versions of
CMake.

It needs some supporting cmake files that are included unmodified,
so GROMACS does not assert copyright on those. The main FindCUDA.cmake
file is modified only to be able to find those files

Refs #2276

Change-Id: I69ad39dc805648a6cc5e27bb7fcd229f5f2a538a