[clang] Introduce `SemaCUDA` (#88559)

This patch moves CUDA-related `Sema` function into new `SemaCUDA` class,
following the recent example of SYCL, OpenACC, and HLSL. This is a part
of the effort to split Sema. Additional context can be found in
https://github.com/llvm/llvm-project/pull/82217,
https://github.com/llvm/llvm-project/pull/84184,
https://github.com/llvm/llvm-project/pull/87634.