[build] Fix for old cmake versions

[ssnl]

Strategy:

1. Move all upstream files to Module_CUDA_fix/upstream/*.
2. Create a custom Module_CUDA_fix/FindCUDA.cmake that first includes upstream/CMakeInitializeConfigs.cmake and then upstream/FindCUDA.cmake so it can be used by submodules too.
3. Remove all instances of include(CMakeInitializeConfigs).

For easier review process, here's how cmake/Module_CUDA_fix looks like after this patch.

@ezyang @soumith @orionr

cc @li-roy @zdevito

[ssnl]

@pytorchbot retest this please

[ngimel]

Thanks for fixing the build! May be it is time to just require newer CMake? (3.10 or whichever has all the FindCUDA stuff).

[ssnl]

@ngimel IIRC @soumith said we want to keep cmake 3.5 (3.9?) support.

[ngimel]

Then may be cmake 3.5 builds should be added to CI?

[ssnl]

@soumith @ezyang should we use older cmake versions in CI to prevent such regressions?

[ezyang]

Yes.